I'm calling a time out! :D:eek:
You might wish to reassess your ability to build your own....between your skill level and now seeing that you live in a condo/apartment. I own a house and do all my plywood cutting outside...will you be able to do that. If you do decide to go forward, you mentioned you had a circular saw. I would make the cuts yourself using a speed square on dimensional lumber and a straight edge that clamped to the plywood to cut the plywood.
The speed square can be had at Harbor Freight for a couple bucks:
HF doesn't have the long cutting guide, but HD has one for about $20:
and
HERE's the link to that cutting guide.
Both of these tools will make sure your circular saw cuts are straight.
Remember, measure twice and cut once! :)
Saw horses would also make the job a bit easier.
And one final note....I see you live in NJ. If you wish to bring your wood over, I'd cut it for you....although I believe Blackwood is pretty far down south.....so far down south, I don't know were it is. Do you guys speak with an accent? :D