Hey brother i only have to add import files in S3 of all the path of girls....Shall i download all the zip files ( ex EP 1 , EP 2 EP3 etc ) and extract them in game folder of S3 or is there any specific file only to add the import files ( i.e path of the girls ) in S3
So which files you need to download depend on your goal.
If you're only interested in having saves for the upcoming episode, I would recommend downloading "Episode 11 Start Saves" and "Season 3 Persistent"
If you want to start Season 3 over from the beginning then I would download "Transfer Data" and put it into your persistent folder in your renpy saves and import the saves from seasons 1&2 when starting season 3.
Usually people just download everything and put them in the proper folders for Being a DIK. I have instructions on how to do that on the post you quoted. As for the saves for specific paths for girls. I have labeled the saves for you, so when you install them it should be pretty easy to see which save is for which girl(s).
Also, I would not recommend using a mod for this game. While there are talented modders that can eventually circumvent DPC traps, they take time. Modding your game will cause errors in the game just as "Mod Detected" prompts, endless dialogue loops, crashes, and halting progression on single renders. If you want to use mod then that's your prerogative but just note it will cause issues for when the next episode drops.
Hope this answers all your questions.