The easiest way to find things is to check return and find the line or box you want to make entry for. Click that line or box and VOILA! you are at or near the entry point. 

I this case you end up at 2021 Estimated Tax ... and scroll down to Paid with Extension (not later than 4/15/2022). There may be a memo amount already there if you prepared the 4868, but you still need to enter the Amount paid