[OmikronWarrior]

The manual for the most part goes over all the basics regarding stealth.

Stealth armies move just like spies. Only the commander and all troops under his command must have stealth. Default movement is "stealth," and you have to hold shift or ctrl (can't remember which off the top of my head, I only seem to know by muscle memory) to move "non-stealthed." Moving without stealth means the army will participate in any military conflicts that occur, or outright attack if moved to an enemy province.

Also, a free tip for MA Vanheim. Skinshifters (though 25% more expensive than their Late Age counterparts) are still the best unit Vanheim has.