Ok from the top in simple terms how do I make disney dining reservations?

can I do it online? if so where please?

how far out do I make them and are they then guaranteed?

is there a way to know how much each will cost in advance?

can I make more than one for the same time so we can choose?

if a place is booked up do they have a wait list?

How much do we have to tip at disney?

and anything else I need to know but havent asked