On most bike tires, there is a small dot of paint on one side of the sidewall.
Be sure to put that dot even with the valve stem. That should put the lightest part of the tire at the heaviest part of the rim.
With tubeless tires, it can be a little difficult to get both beads set enough to hold air for filling. If this is an issue, and you have a ratchet strap handy, put the strap around the diameter of the tire and tighten it down to aid in bead setting.
Sometimes you may need to put more air than reccomended to get the bead set. To help with this, be sure to use some type of lube while putting the tire on the rim. Murphy's Oil soap diluted with water (maybe a couple table spoons to a cup of water) works good. I've also heard of people using talcum powder, but that can end up being a bit messy. The lube can also help with removing the tire, so ya may need a couple of cups worth.
IMO, the toughest part is putting the tire on, especially the last few inches. Don't be in a hurry. Take little steps to get the tire over the rim and the job will be much easier.
Also, once the old tire is off the rim, be sure to clean around the bead area of the rim and check for any knicks or dings.
Oh yeah, be sure to check if the tire is directional and double check that you have it in the right direction.
AKA: Tim & 'The Adventure Cycle' VROC #24567, NEVROC, SteelCity VROC
"When life throws you curves,
Aim for the apex."