If you want to use the ZD1200 you've bought, then plug it into a switch which will give it internet access, and factory reset (poking something into the F/D hole for 10-15 seconds). When it comes back up, log in and check the licenses & support section; you should've picked up 30 days of support entitlement. Upgrade to 18.104.22.168.164, which is a free download, and is an intermediate-signed-image (ISI). Wait for all your APs to upgrade. Once all the APs are on 9.13, you can upgrade your ZoneDirector to 10.5.1.0.124 (a fully-signed image). This will do a factory reset, so don't bother setting anything up under 9.12 or 9.13. Your APs should all upgrade successfully & you're away!
Download and use Firefox to do this. Newer versions of Chrome and Edge don't work properly on old Ruckus releases, so your upgrades will fail.