Modern Vespa

I'm beginning a DIY engine swap on my 2007 Piaggio BV 250 today. Earlier this year while on the highway, it had a coolant leak that blew out quickly, lost most coolant, & overheated, blew gaskets/seals, & engine is toast. I bought a used matching engine through Ebay & today is the day I begin the project. I have a PDF tech manual for my BV to guide me along, but I'm a ROOKIE two-wheel mechanic & would appreciate any advice/insight since I've never attempted anything like this before.
*FYI: My endgame for this BV is to get her running again, inspected/tuned, & then sell it ASAP. I'm planning to upgrade to a Suzuki GW250 standard motorcycle next spring/summer (if they ever arrive here in the U.S.A.).