I hate how this information is so spread out so I will try to condense this:

(1) Register your domain name and setup email (GSuite is simple enough). I put this first, because it is nice to have all the business communications actually going to the business email, so you don't start intermixing with your personal email.

(2) Next, I'd recommend hiring a local lawyer for the LLC filing and paperwork, not because you can't do it yourself, but because they can do it a lot faster and will help find any mistakes throughout the entire process. (they do this all the time) You will basically end up using them to file the Articles of Organization, act as your registered agent (avoids having to put your name and address directly on file with the SoS office), and they typically have boiler plate Operating Agreements that you can use to bootstrap your own.

(3) Next, you (or your lawyer) need to file Articles of Organization with the Secretary of State's office and pay the filing fee. (Normally $100 or so) You'll typically have to renew this registration annually. Your lawyer can take care of it.

(4) You then need to decide how you will be taxed. Your basic choices are to be taxed like a sole proprietorship or as an S Corp. I would choose S corp, so that you can save on taxes. When you go this route you will select a "reasonable salary" for yourself to be paid. Anything you earn above and beyond your reasonable salary you can take as a distribution from the company, which is not subject to self-employment taxes. If you go the sole proprietor route it is simpler (you report income on your schedule c for the IRS), but everything is subject to self-employment taxes.

(5) If going the S Corp route you will want to obtain an FEIN(https://www.irs.gov/businesses/small-businesses-self-employe...) and file form 2553 with the IRS for the subchapter S election. You have a limited window to do this, so do it shortly after filing the Articles of Organization. If you have an accountant they can assist you or do this for you.
(6) Next I'd recommend getting a payroll company to run your payroll if you've gone the S Corp route. (Something like Square Payroll https://squareup.com/payroll/) They take care of filing all the required forms with your state and will make it really easy for you should you ever add additional employees beyond yourself. What are some of these forms? They vary by state, but to give you an idea here is a look at the items for the state of Oklahoma (https://squareup.com/help/us/en/article/6319?utm_medium=web&...):

- Withholding Payment Coupon (WTH 10004)

- Wage Withholding Tax Return (WTH 10001)

- Transmittal of Wage and Tax Statements (OK W-3)

- Wage and Tax Statement (W-2)

- Employer's Quarterly Contribution Report (OES-3)

- New Hire Report

(7) This leads to the next item, which is you likely need to register for a state tax ID and a state unemployment insurance ID and then input those IDs into your payroll provider's system. Again this varies by state, but normally each state has some analog of this.

(8) Make sure you create an Operating Agreement. It is an important governance document for your LLC. Your lawyer can help bootstrap you here or you can find samples online. Although, not strictly required it is an important document in establishing your LLC as a legitimate LLC and not just an extension of yourself. It helps prevent "piercing of the corporate veil" in instances where you might be sued. (i.e. keeping your personal assets protected in the event of a lawsuit)

(9) Hire an accountant (if you haven't already) to handle the K-1s and taxes of the LLC. This saves you time and potential penalties that you might run into in making a mistake with filing.

(10) Use some software like Quickbooks Online or similar to track your accounting. Bonus here if your payroll feeds directly into your accounting software.

(11) Get a Small Business Credit Card like this one from AMEX (https://www.americanexpress.com/us/credit-cards/business/bus...). You are going to have expenses and you might as well get some points while you're at it. Also, easier to track expenses. The bonus with these too is if you add employees then their travel expenses are tracked and you get the points for them as well.

That's all the basics to get the LLC operational. Obviously there are things like business plans, industry specific compliance regulations and certifications(not typical of software companies though), health insurance, etc., but this is a basic list to meet the requirements of the federal and state government. Good luck!