I want to make clones vs rebels.
For example on Geonosis the CIS has these spiderwalkers.Can I just replace the spiderwalker with any alliance vehicle in the ODF?
Or do I have to make somethng with ZeroEditor?

You should implement the neccessary infomation in the .lua file.
In the Zeroeditor you also have to go to the vehiclespawns. In the Information box (after selected the object mode and got to one of them) you have to go a page down and insert the names of the files you want to spawn there. That's it.

Hope you can follow my explanation

thanks I will try later