You need to spwan in AI units when you create a FOB. You want to select AI Recon Squad, AT Squad etc Build crew option.. Then you can control AI's using Zeus. Someone told me to try Ares mod which I have not tried yet. Hope this helps you.

the ares mod is a good one to have when playing as zeus

but i want to spawn my own units not with a fob

you need to edit the mission to do that