Depending upon the layout and the table style, it's easy to move one solo.
There are very few that I'm not 100% confident on doing alone.
IF you can carry at least a couple of hundred pounds, for a good distance while being careful of your surroundings, there is the hardest part of the job.
Provided it's a three piece slate.
One piece, need a hand usually, and some dollys, just to protect things a bit more.
How many stairs, how many turns, width, height of staircase, are all part of the factors needed to provide an accurate description.
But, to be honest, if you are here asking how to do it alone..... you need to bring some extra hands and backs.
It'll be cheaper in the long run for you, and if you haven't done it to get the techniques down for carrying it, your back will thank you also.
Other than that, disassemble it as far as you are able to, and make a few trips.