[Galaxy Tab S2 Android Development] filker0:
I am having trouble with this, perhaps because some assumptions are made that I am missing. There are over 120 pages of postings in this thread, so I may have missed what I'm looking for.

I have a Tab S2 model SM-710 with the stock Samsung Android 7.0, latest security update was 2018-04-01.

I downloaded "lineage-18.1-20211103-UNOFFICIAL-gts28wifi.zip" from supplied link, got "opengapps-arm64-11.0-aroma-20220503.zip" from SourceForge, and grabbed "Magisk-v25.2.apk" from the GITHub repository.

I am using the "FULL WIPE (with external microsd card)" option.

I backed up all my apps to the SD card, then copied the downloaded files to the root of the SD card, booted into recovery mode, and saw the following:

Android Recovery
samsung/gts28wifixx/gts28wifi
7.0/NRD90M/T710XXU2DRG2
user/release-keys
Use volume up/down and power.
Reboot system now
Reboot to bootloader
Apply update from ADB
Apply update from SD card
Wipe data/factory reset
Wipe cahce partition
Mount /system
View recovery logs
Run graphics test
Power off

The menu and recovery UI does not match what is in the instructions

"Wipe data/factory reset" seems to wipe everything and reformat the data partition

"Wipe cache partition" clears only the cache partiton

I did the factory reset and explicitly wiped the cache partition, then I attempted to install the ROM from the SD card. This failed:

No Support SINGLE-SKU
Supported API: 3

# MANUAL MODE v1.0.0#
-- Appling Multi-CSC...
Applied the CSC-code : XAR
Successfully applied multi-CSC

Successfully verify for dmverity hash tree

-- Wiping cache...
Cache wipe complete.
-- Start Factory Reset...

-- Wiping data...
Formatting /data...
Formatting /cache...
-- Set Factory Reset done...
Data wipe complete.

-- Install /sdcard/lineage-18.1-2021103-UNOFFICIAL-gts28wifi.zip ...
Finding update package...
Opening update package...
Verifying update package...
E:failed to verify whole-file signature
Update package verification took 30.0 s (result 1).
E:signature verification failed
Finding update package...
Opening update package...
Verifying update package...
E:failed to verify whole-file signature
Update package verification took 31.4 s (result 1).
E:signature verification failed

Successfully verify for dmvverity hash tree
Installation aborted.#1

So a few questions come to mind:

Is there an assumption that I've replaced the recovery image prior to starting this process? The original post recommends having the latest firmware before starting, and as far as I can tell, I do.

If the answer to question #1 is "Yes", what recovery should I install, and how do I get it (a URL to a thread for that would be appreciated)?

Where does the "Magisk" application come into this? It is linked, but I didn't see anything in the post that references it.

Is there anything else that I'm missing?

I dropped into the "Tab S2 Universe" Telegram and posted some questions, but have not gotten any reply, and I may have been kicked by the the "shieldy_bot" because I didn't do something it expects me to do -- the channel now says "1 member" and it disappeared from my active channels list. (Edit: It appears that I've been banned, not just dropped, from the group, as I now get a message telling me the group is not available to me when I try to join it again.)

I would appreciate any help I can get on this. I don't mind the device going back to "factory", as it is not a main-driver for me these days, but I would like it to be made useful, and Android 7 is no longer supported.

Thanks.