Help/Support Custom install Questions

[BipoIarBear 62 iPhone 12 Pro Max 15.0]

I am a newb at this this whole Custom install to save your game process. I am wanting to get this down packed and understand how to do it completely because I don't want to start again and lose my process again. I have read the Custom install thread which shows me how to create duplicate apps but am not sure from there. 

I have installed the IOS APP+ and I have custom installed the app which does not have a save feature. 
I am wondering how then I am able to access the save.. I clicked the file sharing in the custom install!

I have then gone to iTunes and have found the IOS APP+ in the file sharing and the IPA's of the apps I have downloaded. 

Do I just save the IPA and that will have the game save within the IPA? 
Do I then just re-install that IPA onto my phone with Impactor after a revoke and that will have my game from where I left off?

 

I am a newb and any help will be much apprciated. Just cant figure it out 

[Laxus 824.9k iPhone 5s 10.3.3]

Custom install the game with uifilesharing option on. Then use iFunBox or 3uTools and you can open the app save file just like App+