I have one and love it! It is one of the more popular upper end lathes in the USA. You should be able to google the term mustard monster to find the link to a web site for Powermatic 3520 user tips and tricks.
I used the saw horse technique but three old guys can safely roll the lathe bed up off the floor after installing the legs. I used this technique to help a friend with his. The user manual describes the assembly process. You can download the manual from the Powermatic website. The manual actually specifies a forklift to assist with assembly but not too many of us with access and not really necessary. The bed is about 200 lbs and each leg about 85 lb. The tailstock is about 57 lb. The motor and headstock is probably about 125 lbs.
Don’t attempt to assemble by yourself.
