No problem, I won't regret it. We're all in this together!

You may not have estimates for each work package, but you can (and should) start on the network diagram. It's basically just a flow chart that sequences work packages and graphically depicts dependencies. You'll need this before you do any scheduling.

I googled for a network diagram and here's a picture. Each box is a work package. Each work package should have a number to uniquely identify it. Work packages say "what" gets done by "whom", the network diagram says what order it gets done in. The schedule (at the end) will say "when", based on resource constraints.

Jim