It will basically be every so many levels you get a Spell-Like Ability. You then apply affects to it to change what it does. For example lets say one is Blast. It does 1d6 damage per level on a successful ranged attack roll with a range of 60'. Effects you get every so many levels allow you to change the damage type or add descriptors, or add possible effects such as a save or be stunned. Meta abilities you get every so many levels allow you to apply effects similar to metamagic feats every so many rounds. For example an empowered blast you could use, but you need to wait 3 more rounds before using again.