The AbilityBook library has a lot to it, but here's some quick and dirty descriptions and parameters. I'd highly recommend digging into the AbilityAMPs and Abilities addons to get a better idea of how they're used.
GetEldanAugmentationData(idSpec): This function will get you a table with information on the AMPs available to the character. You need to pass in the number of the spec that you're editing, which you can get from AbilityBook.GetCurrentSpec().
UpdateEldanAugmentationSpec(idAmp): This will set an amp in the current spec. Note: This will not commit the change! The information is cached until RequestActionSetChanges is called.
RequestActionSetChanges(arSpellIds): This will commit changes to the current spec's AMPs and abilities. It takes in an array of spell ids for each spell in the LAS, in order. If a slot is blank, the id should be 0.
RespecEldanAugmentations(eRespecType, nId): This is used to reset anything from a single AMP to everything in the player's current spec. eRespecType comes from the AbilityBook.CodeEnumAMPRespecType enum. If you're respecing a category of AMPs, then nId is the category's id. If you're doing a single AMP, then the AMP's id is used. If no information is passed in, then this will attempt to do a full reset of the player's AMPs.
GetEldanAugmentationRespecCost(eRespecType, nId): This will return the number of credits (in copper) that the player needs to pay for a respec. The parameters work exactly like RespecEldanAugmentations. It's worth noting that cached AMPs that haven't been committed cost nothing to reset.
GetAvailablePower(): This is important since it gets the amount of unused AMP power the character has. This value does take cached changes into account.
I think that should be enough to get you started. Again, I highly recommend checking out the AbilityAMPs and Abilities addons to see how all of it works together. I hope this helps!