if i have 2 files the program and 1 self extracting archive can i add both to the same addonpack

also can i load a bat file from the addon how would i achieve this

I'm not sure I understand your questions. On the second one, I presume you mean you want to run a batch file during setup. Why not place your bat file in the $OEM$ folders (like $OEM$\$1\my.bat) and call it from GUIRunOnce (%SYSTEMDRIVE%\my.bat) ?

The answer is yes to both questions.

To execute a batch file from SvcPack.inf you must place the file in the SvcPack directory and execute it as you would any SvcPack installer.

yeah dont know much about run once or batch files so hard to explain lol

i was more thinking if running a batch file in my addon could it be added to entries.ini or would i have to combine and create the 2 files as 1 switchless installer with the batch file being called from inside the installer

You don't need to combine them into a single installer unless you want to.