hi guys, im not new, just forgot my old password to other name but I haven't been on here or had TS since like 2013. major problem im having is that some of the assets now are in .ap files

and im trying to add reskins to them, at first I couldn't figure out how to open them up and add the new skins into them but I found out 7zip will unzip it for me, but how can I make it an ap file again to add it where it does? and yes ive read around the net and the lil I found is confusing as hell so help would be appreciated, thank you guys