While defending my castle, does garrison or my own party spawn first?

My garrison list puts a bunch of archers at the top, which is fine. But I'm also going to need a bunch of infantry at the beginning, since the Khanate outnumbers me 10 to 1. I need to hold the wall from the very beginning.

So, if I put a bunch of Huscurls at the top of my party list, will they spawn first? Or does my garrison spawn first? Or do soldiers spawn from both lists simultaneously?