Well, I hope I understand your question correctly and it appears you are very new to this - we all were at one point. I think you mean ARV (assessed retail value or after repair value) instead of "AVR".
Are you looking to flip properties, focus on appreciation long term, or rent them out. Regardless, you're going to need to estimate the up front costs, estimate the costs to keep the property for "x" amount of time, and then figure out what your "out" is.
So, for starters, whether you're flipping or renting, you're going to need to know the amount of money you have available to work with - realistically - and then from there form an opinion on if you can move forward with your goals and where those goals should be aligned or if you need to have more patience and save a bit more money.
Once you have an idea of the type of properties you're going to be buying and what you can realistically afford, it's time to start crunching the numbers. Attempting to flip a property can be relatively speculative for an absolute newbie, and you'll be at the mercy of contractors (or your own skills) at figuring out the rehab costs. All too often these rehab costs get estimated too low, so definitely keep a buffer there.
In addition to that, you're also going to need to have a time line of how long those goals are going to take to reach and don't count on the contractor meeting their dead lines, again have a buffer. These time lines become important, because you're going to be holding onto the property for a few months perhaps (or longer) and you're going to be responsible for utilities, insurance, taxes, etc - each day you own a property is essentially costing you money. If you live in the area, you should have a good idea of what utilities might run, assessors pages can give you an idea of taxes (be sure to account for any deductions existing you won't receive), and your insurance agent can estimate insurance.
Lastly, to get the Assessed Retail Value or After Repair Value, you'll need to check out and see what similar homes in the area are selling for and talk to real estate agents. You can maybe use county records to see what the assessors report has for the tax value of the property, but keep in mind it may not be absolutely in line with the current demand.
So essentially, what you need to know when analyzing each deal is what the home can realistically sell for in your area based upon similar, recent sales and then you subtract from that what it is going to cost you to actually purchase the property up front and what it is going to take to rehab it and then further more subtract the total costs of ownership (utilities, insurance, loan, etc) for the period of how long it will take to sell the house - and obviously that can be tricky. Make sure the reward well outweighs the risk.