app syncing problem , help plz

its all well and good transferring purchases to copy apps from ipad to itunes but im yet to turn on app sync and having to use icloud to restore if i want my apps

i know lots having this issue , but wana fit it and sync all apps

if i check the box for sync apps i will lose half my apps and gain ones i used to have few years ago so how can i clear it and sync new apps and check the apps i already have on my ipad

hope this question makes scene

 

bump anyone