It may seem overwhelming but maybe try planting one section at a time, using a hose to outline a shape for a bed perhaps and then maybe adding some compost or planting mix and taking the plants and setting them out to decide what goes where. Sort the plants by what you feel would go well together.
When I moved 5 years ago, I brought about 600 potted plants with me and started one section at a time.
http://garden.org/thread/view_...
It felt so overwhelming at first but just getting a few things in and seeing how the plants took off and filled in encouraged me to keep plugging away at it and obviously the plants were happy to finally have the root space to take off! I have maybe 20 plants still in pots from those original 600, I feel so sorry for them!
But I have my goal to get them all in this year. I promised them, yes, I actually told them that,
and writing it here now I really have to keep my promise!