PokeFinder has the ability to set up profiles for each of your individual saves. By setting up a profile for a save, you can have information such as TID/SID readily available. This is useful because you only need to input save specific information once, and then it's available every time you relaunch PokeFinder.
Open PokeFinder and navigate to "Gen 8 Tools" -> "Profile Manager".
Select "New" and input the info needed to create a profile for your game.
For TID and SID, these values will be the 5 digit values displayed in either CaptureSight or PkHeX (hover over the TID box to see this).
This will only have to be done once for each profile you set up.
Menu Options
In the opening screen of PokeFinder there are options for which type of RNG you are doing sorted by generation. You will want to pick the correct one for the Pokemon you are going to RNG.
Static - for Pokemon found in the overworld, roaming Pokemon, or Pokemon received as gifts
Wild - for Pokemon found in the wild, such as grass, surfing, etc.
Within the different RNG method screens there are inputs for Seed 0 and Seed 1. Take note that if you are using CaptureSight to view the RNG seeds there are 4 seeds displayed. To input the 4 seeds from CaptureSight into PokeFinder use the following:
Seed 0 of PokeFinder = Seed 0 and Seed 1 of CaptureSight
Seed 1 of PokeFinder = Seed 2 and Seed 3 of CaptureSight