[Nintendo Switch News, Guides, Discussion , Develop] gorei23:
This guide was created for people who are not as familiar with the world of Switch exploits.

NOTE: This is not the official ROM thread! DO NOT ask questions about using, troubleshooting, etc. the ROM here. I will not be able to help you and it splits discussion. Please ask questions, tips, etc, in the official thread! This post is purely to guide users in setting up their PC and such for installing this on their Switch.

DISCLAIMER: Everything is done at your own risk. Use common sense.

What you will need:

An RCM exploitable Switch console. Check here to see if your device is exploitable. If you have a newer device an exploit may be possible on older firmwares, but if you haven't already set it up you probably updated to a too new version already. Read more here. (for non-RCM exploitable devices)

A jig or other method of triggering RCM. Here's a few methods. Premade jigs can be found online.

A computer. (Assuming a Windows PC for the purposes of this guide)

A good USB-C cable that can connect to your PC and Switch.

A high quality, high speed microSD card of at least 16GB.

A way to read microSD cards on your PC.

Required downloads:

The ROM, find it in the Downloads section of the first post. Select the SD Card size that matches yours. Read through the post as well for latest information.

If desired (but not required), the shield-ifier.zip and/or the Reboot2Payload zipfile also in the ROM downloads section. Shieldifier should allow you to download games meant for the NVIDIA Shield. Reboot2Payload means you'll reboot to Android when you hit "reboot" within Android (or Hekate if you choose reboot to bootloader). Without it you'll reboot to the default OS.

GApps, AKA Google Apps. This will install the Play Store and other Google services. Not required but 95% of people will want this. Select ARM64, 8.1, and then any on the right (Nano is recommended). Hover your mouse over each option for descriptions. If you're not sure just choose Nano.

TegraRcmGUI. This program will push the exploit to your Switch. Grab the latest .msi installer and install it.

balenaEtcher. This program will write the ROM to your SD card.

Hekate. This is the "bootloader" if you will. Once you get to RCM with your jig (or whatever method) this is the payload we'll be sending over. The ROM developer recommends using version 5.0 exactly, and I'll recommend that. Version 5.2+ however does include support for partitioning your SD card so you can use one SD card for Horizon (Switch's default OS) and Android, though I have not been able to figure it out.

I recommend putting the ROM, GApps, shieldifier, Reboot2Payload, and Hekate files all in one folder so your Downloads folder doesn't get cluttered.

Steps:

Insert your SD card into your PC. Backup anything you need to because all data on the card will be wiped.

Open balenaEtcher. Select the "android-XXgb.img.gz" file you downloaded. In the middle make ABSOLUTELY sure the device selected is the SD card you want to use. You don't want to accidentally destroy some other drive you have attached. Click "flash". This can take a while (30mins-hours depending on SD card speed and size!), especially on larger cards. The progress bar will jump around, and get stuck at like 99%. Don't worry, that's fine.

Once it's complete you can close balenaEtcher. You should be able to see two new drives in Windows explorer. One will give an error if clicked (Don't click format when Windows asks!) and another is a 2gb partition Windows can read. If these don't appear then reinsert your SD card into your PC. Mine mounted the unreadable partition as D:\ and the readable one as S:\. EDIT:Redoing this months later it only shows the one drive for me.

Place the GApps .zip (and shieldifier/Reboot2Payload .zip) file(s) in the root of the 2gb partition. Don't unzip them.

Eject the SD Card from your PC and place it in your Switch.

Use your preferred method of booting into RCM. I posted a link with many methods in the "What you need" list up top. You'll know you're in RCM when the Switch screen stays black and doesn't boot as normal when you hold Power+Vol Up.

Launch TegraRcmGUI. Go to the settings tab and select "Install driver". Go back to the payload tab and select the Hekate .bin file as your payload. Connect your Switch. It should say "RCM OK" in TegraRcmGUI. Now select "Inject Payload". Once you see the GUI on your Switch then you can disconnect it.

Tap "More Configs" and then hold down Vol Up and tap "Switchroot Android". Continue holding Vol Up until you get to the TWRP menu.

Tap "Keep Read Only" on the first screen.

Tap "Mount" and check "System" and "Vendor". Then tap the home button at the bottom. (If they don't appear, move your finger up and down in the middle and it should refresh, try that every time it looks like things are missing in TWRP.)

Tap "Install", then "Select Storage", then "Micro SD card" and "OK". Tap the GApps zip, uncheck "Reboot after installation is complete" and slide the slider to the right. Optionally do the same for shieldifier and Reboot2Payload (press back after GAPPS flash to go back). Once finished with all zips wipe the Dalvik cache (it will prompt you). NOTE: If you want GAPPS you MUST install GAPPS before you first boot up Android, so if you accidentally booted into Android, reflash your SD card and restart the guide (you may be able to wipe data and caches through TWRP to fix it, I haven't tested).

Select "Do not install" if it asks to install the TWRP app. Reboot the device (you may have to hold the power button), enter RCM again, and re-inject hekate from your PC. Boot Android again but this time don't hold any buttons. Your screen may be black for a minute, don't panic. First boot takes a while.

Your device should boot into android. Congratulations. Update the NVIDIA Shield app through the Play Store if you installed it. For setting up anything else, or for questions you may have, use the official thread.

NOTE: This is not the official ROM thread! DO NOT ask questions about using, troubleshooting, etc. the ROM here. I will not be able to help you and it splits discussion. Please ask questions, tips, etc, in the official thread! This post is purely to guide users in setting up their PC and such for installing this on their Switch.