There are many ways to get the slabs on top of the base - just don’t use the, “I’ll get my son’s football team to come over and put them on for me” route. You want these guys to like your kid…
Don’t over-think it… 2 people can easily put on a slab with little effort and do not lift them straight up - that is just too much work! Here’s one super easy way to elevate a slab…
Lay the slab next to the base and lift one side (Side A). Place 2 bags of concrete UNDER Side A. Now go to the other side (Side B), lift, and put 2 bags of concrete under Side B. Congrats, you just got the slab 16" off the ground with little effort. Do this a few more times and your slab will be parallel with the top of the base in no time!