Hi, Pbd. Fan/emotional supporter of artists here, and sometime accountant. Here are starting points and some completion criteria - in hopes of finishing the process so you can return to your art!
1. I don't really budget either, and that's fine. Detailed budgets can be helpful but are a fine point. You can get a basic handle on your situation - what the engineers might call "a first-order approximation" - just by analyzing your previous spending. Think of it as the pencil drawing that da Vinci sketched out before painting - it shows the outline and hints of detail, enough to get an idea. You just need some spending data in order to evaluate your situation.
2a. If you've been using a bank account, Mint will let you download info from it into Mint. Mint is free, you can download it from mint.com. Mint will help you by offering a tentative classification of the expenses that can be used a basis for budgeting in case you want to go the budget route. Same for any spending that you did via credit cards - you can download it into Mint.
2b. If you don't want to learn Mint, but you have a bank account, get a copy of a spreadsheet program such as Excel or one of its free sisters, such as LibreOffice. If you're using a laptop or desktop, you probably have one of these already.
https://www.scoro.com/blog/11-user-friendly-excel-alternatives/2c. You can download data from your bank account into the spreadsheet. There's an option for that in your bank's website. Call their customer service if you need help. Same for your credit cards, if you have any. Downloading this data will cover your past 12 months of expenses, except for any cash transactions. 12 months is a length of time that most companies retain, and is long enough to make most month-to-month variations in your spending average out.
2d. Depending on how many cash transactions you have, either some or all of your spending can be captured in this way. But you need to add in the cash too. Do your best to guess how much cash you spent, and add that in. Remember that if you got cash from bank withdrawals or by depositing checks, the bank data includes withdrawal and deposit records that you can use to approximate the cash amounts.
3. Once you have the above financial data, analyze it as follows.
3a. Separate all the incoming money (deposits) and all of the expenses. Add them up separately. Mint or the spreadsheet has ways of doing this very quickly. Let us or your office-y friends know if you have any difficulty with this.
3b. Your expenses for the year are the basis for the rest of the planning.
3c. You can reasonably expect to live off your investments forever if you have at least 25 times as much money in investments as you have in your annual spending. It's a rule of thumb, but it means you're in the right ballpark. Just remember that if you spent any cash, you need to somehow include it in the expense amount before you do the "times 25" part. Mr. Money Mustache has a good article on this 25x rule, also known as the 4% rule. (Saying "spending is 4% of investments" is mathematically the same as "investments are 25 times as much as spending").
http://www.mrmoneymustache.com/2012/05/29/how-much-do-i-need-for-retirement/4. If you have enough to maintain your current spending from the inheritance based on the 4% rule, you are now free to create art the rest of your life without selling your art. Of course you can keep selling if you like, you're just free.
5a. If the inheritance doesn't cover your spending, but you'd like to be completely free as an artist, you still need to save more, or else to cut expenses to the point where your expenses are covered by your investments. MMM's article below covers how to calculate how long this will take. Use the inheritance to cover some of the years - ask for details if this isn't self explanatory after reading.
http://www.mrmoneymustache.com/2012/01/13/the-shockingly-simple-math-behind-early-retirement/5b. In the meantime, you can improve your stability by maintaining at least a few months' spending as an emergency reserve, aka "prudent reserve."
5c. Above that, use the power of additional savings as...F-U money!
http://jlcollinsnh.com/2011/06/06/why-you-need-f-you-money/6. If you want savings tips, the case study will probably get you detailed ones.