These things always take twice as long as you expect.
Do you have to cut any wood, or is it all precut?
If you are cutting wood it could take two days.
It's good you have help, you definately need a second person during lifting and final assembly.
Make sure that you have a socket wrench and maybe a cordless drill.
Also get a plastic bin or tray to put all the hardware in, you don't want to loose anything.
Is it going on level ground?
My yard has a slope and I had to built a base under one side and bury the other.
Make sure the area you are placing it in is all set.
Also check for any branches that may be in the way.
You also need some beers, but wait until you are almost done.

Good luck!