This forum is to be used for all discussions pertaining to Black Isle Studios' Icewind Dale and its Heart of Winter and Trials of the Luremaster expansions.
Having trouble how? Are you having trouble finding new spells, or having trouble with the mechanisms of putting more spells into the book?
If the latter, you can right-click on any mage spell scroll and use the button at the bottom called "Write Spell" or something like that.
To change the spells you have memorized, go to the spellbook icon on the left side, as Woundead said, and click on the spells you want. Do this before you rest, as you have to rest before the spells become memorized.
When your back is against the wall... the other guy is in a whole lotta trouble.