With regards to studying away from the table. A lot of GTO analysis comes down to studying hand combinations.

So as a very general example. Villain opens pre and you defend 10% of your range.
10% of 1326 total possible combos is ~130 (rounding from 132 for simple math purposes)
If villain bets pot on the flop, he's risking 1 for 1, so his bet needs to work 50% of the time. This means you need to defend (call or raise) with 50% of your range.
Flop defending range = 130*50% = 65 combos
Turn villain bets pot, you need to defend another 50% = 32 combos (approx)
River villain bets pot, you need to defend another 50% = 16 combos.

The defense percent won't be 50% by street, it will probably be closer to 60% because most villains will bet around 2/3 pot. But the method is the same.

Once you know how many combos you need to defend by street, you need to look at your starting range (130 combos) and break that down by street into the appropriate number of hands that will be continuing/defending.

It's a process that takes a lot of time, but after doing this exercise on different board combinations (Axx, Kxx, QJ9, 722 rainbow/twotone etc) you'll start to develop patterns of types of hands that need to call down to defend appropriately. You'll notice boards where it's easy to defend appropriately and boards where it's hard, and you can exploit this fact in villains ranges.

Sorry for the long rant!