Can I report early? And how?

You're allowed to report 30 days early, but when you're flying OCONUS most port call places will not allow you to fly outside a small window of your report date.
It just takes a 4187 to your career counselor, request 60 days early report authorized in your special instructions. Battalion commander needs to sign it.

If you’ve received your orders check to see if they have early report authorized. If it’s in your orders it’s up to your loosing command to allow you to depart early or not. Also, once you get to Germany you will have to apply for command sponsorship in order to be authorized housing and to receive the OHA for overseas. You won’t be able to apply prior to the assignment because your wife had to do an EFMP Screening regardless if she’s a local national. Upon your arrival you will be required to live in the barracks until your command sponsorship is approved... I hope this helps...good luck to you.