I need to build a deck with three platforms at different levels.
I have built decks before but none having large deck platforms at different levels linked together.
Basically, two free standing deck platforms and one platform connected to the house.
Does anyone know where I can get an idea of what the framing looks like?
The positions of piers, girders, joists to be specific.
Thanks.

You can find idea books on deck building at any home store - probably the best place to start. You will not find anything exactly like what you are looking for, but it may be enough to fill in the blanks.

If that doesn't work, then i have to fall back onto the same advice i seem to give over and over and over again on these boards: Hire a pro. A multi-level deck is complex - it needs to work for structure, for aesthetics and and for egress. If you do not have the skills needed to make a workable design then you have no choice but to seek out professional help. A design/build construction firm could do this easily.