There are manuals available for all years that explain it. If yours has the IQ-2000 controller, this manual will work:
https://www.thespaworks.com/sites/default/files/solana_owners-manual_00.pdf
There are also schematics inside of the cover for the control unit. It's basically a matter of moving one jumper on the right side of the board, removing two jumpers where the current power cord is connected, and connecting two circuits from a sub-panel. Do you have 220 service to a subpanel near the tub? If so, you'll need a 20amp 110 GFCI breaker and a 30 amp 230 GFCI breaker, and a liquid-tight whip with four leads and ground.
For me, the most expensive thing was running 75 feet of 6 AWG romex, which cost almost $500 just for the wire. The breakers are around $90 apiece and the sub panel is less than $50. The whip was somewhere around $100.
I never ran it on 110, but I can feel when the heat is on at the same time as the jets pretty much any time we get in, so I know we would have been disappointed if we had tried to operate it on 110.