Are you just replacing a tube? Are you experienced in taking a tire off?
If so, remove the valve core, take the nut off and push the valve stem into the tire, just remove one side of the tire on the side away from the sprocket, except on an RE this doesn't matter. Be careful not to catch the tube under the tire iron. Then pull the tube out through the gap between the tire and rim.
Sprinkle some talcum powder into the tire and swirl it around so there is an even coating. If you have a bunch left over in there, dump it out.
Push the new tube into the tire, making sure it is all the way in, work the valve stem through the rim hole, and put the not on just turning it down a few turns, do not bottom it out. Put the valve core in and add a little air so the tube takes a little shape. Do not put very much it or it will be difficult to get the tire back on the rim, but you want enough to keep the tube from getting between the rim and tire. Again be careful with the tire irons. Make sure the stem is vertical and fill it with air. You may want to overfill it a bit to make sure the tire is seated on the rim.
I don't run the nut down on the stem all the way so if the the tire should slip on the rim and pull the tube, it won't yank the stem off.
Bare