If I remember correctly, you rolled two dice and thats how many cards were given out, starting by dealing to the person whos magic phase it was. Each player then took it in turns to cast and dispel starting with the player whos turn it was.
All dispelling was done on randomly dealt cards, with high elfs able to use power cards as dispel, and dark elfs dispel cards as power. There was also miscasts and irresistables in there too. If you had higher level mages, the enemy was on a base 5+ to dispel, equal it was 4+ and if your wizard dispelling was higher than theirs it was a 3+. By spending extra power cards, both sides could move the dispel number up or down by fortifying their offence or defence.
At the end of the magic phase, you could keep one card per wizard in your army, plus any extra you were able to keep with magic items.