I have the files all in their own folder, the .exe and the two .bin files with the original names from downloading them but the installer refuses to recognize the .bin. I have tried having it look into the folder and directly at the file but to no avail. (running as admin ofcourse.) Is there something im missing?

(The default names were 'setup_fallout_tactics_2.0.0.8-1' with the -1 being either gone or -2 for the others.)

The filenames are these:
setup_fallout_tactics_2.0.0.8.exe
setup_fallout_tactics_2.0.0.8-1.bin
setup_fallout_tactics_2.0.0.8-2.bin

If they're all in the same folder and the EXE-installer doesn't find the bin-files, they're probably renamed somehow.

Don't change any filenames before or after downloading, just save them. The file-extension ".bin" might be invisible on your system (by default Windows hides them). (Maybe you're now using files that are named setup_fallout_tactics_2.0.0.8-1.bin.bin, while the second .bin is hidden)

I'd start anew with a fresh download and without any download managers.
Alternatively you could try the GOG.com Downloader.