You can mount it however you want.

It's up to you.

Thrust angles are set by the firewall.

As long as you have the engine "square" in it's mount, the thrust angles will be good.

This is by no means a beginners plane.

If you haven't done so, please join a club, and get certified.

If possible wait on this plane until you've built another plane or two that is better documented for novices.

Also you can download manuals for similiar planes from other manufacturers as guides. Try to download manuals for planes of the same size and of similiar type... there are a lot of good tips in the manuals.