If the guy put it into storage correctly (closing the gas tank petcock) then all you need to do is drain the gas tank, put in a carb/FI cleaner additive in the new gas. You can probably just syphon it out as mentioned by Elwood or you can take the tank off and dump it out. I also agree with Elwood on replacing the fuel filter.
If the guy just parked it one day and didn’t turn the fuel petcock off. After sitting for five year I would take the carb out for a clean/rebuild. Also do the fuel filter, new gas and additive.
If not kept in doors I would also check out your fork seals, how rusty the chain is. Check out the airfilter and see if the tires look dry rotted. Change the oil/oil filter as well. Check your brake fluid and your fork action to make sure they are acting fine.
I’m sure you have done most of this, just brain dumping.