How does soulbound work

Check the options. There's an option to set the map's default angle to 45 degrees (default) or 0 degrees as well as some options to change hotkeys and there's where you'll find the defaults for rotating the map (which I don't know off the top of my head but I believe they're Q and E). You have to unlock the map for rotation in the options though before you can use Q and E, this is of course assuming that those are the right keys to do it with.

As a beginner to the game, I found the easiest class to play for farming gods was a Priest.

It sounds a bit odd, but priests use the longest range main weapon in the game (wands), and they can heal themselves. So you can just sit back and shoot gods off the screen. When you take some damage, pop your heal spell.

In addition to that, Priests have great natural speed, so avoiding damage is easier than with a slower character.