How to delete a custom deck on the ipad version of hearthstone

N.O.V.A. should be saving your progress automatically, and there should be a continue option at the top of your menu the next time your game starts.

If it doesn't, your best bet is to re-install the game, as this usually seems to work for others who had the same problem.

I assume you're already on the spellbook page (by using the spellbook icon in the circles on the bottom left).

To get information on a spell, tap and hold on a spell in your active list (left side) or learned list (right side). To switch them out, tap a spell in the active list once - a single pixel border should appear around the spell slot - then tap a spell in the learned list. The spell slot should be filled with the spell from the right.

This is all way easier to do on an iPad than an iPhone. It seems like the tap version of the game was built for the iPad experience and just scaled down for the iPhone, making all the tap targets extremely small.