Its pretty easy process for me. I can change the actual water in about 5 minutes.
I pre-mix RO water and salt in a 20 gallon rubbermaid trashcan with a powerhead and heater for at least 24 hours.
I turn off the power to everything (heaters, powerheads, filter, etc) to avoid any heaters from breaking and water messes.
I use a gravel vac to siphon the water from the tank into a second 20 gallon trashcan.
Finally, I siphon the new water into a smaller trashcan (5 gallons or so) so that I can lift it above the tank. Water is then siphoned into the tank.
Once the water level is back up the power comes back on.
I'm sure others have methods that work for them. The only difficult part with mine is lifting the new water high enough to get a siphon going.
