This video shows how my wife and I moved our 5'8" grand piano out of a room to put a large area rug down and then move it back.

Here are a few items that I forgot to mention. Each tridolly is rated for 300 Lbs. I also uninstalled a ceiling fan while the piano was out of the way which gave me a place to later install a chandelier. If you have your choice of vinyl floor material, get the thickest that you can or plan to use two layers. Mine was barely sufficient to prevent the wheels from sinking.

I hope this video helps you.
Tom