How to Fix a Flat Tire on a Bike

1. Wear gloves. If wearing disposable gloves, pull them off by the fingertips first to prevent them from going inside out, so they can be reused.
2. Put the bike upside down. For my e-bike, before putting the bike upside down you have to adjust the screen to be lower to protect it, remove the kickstand and battery, and unplug the wire going into the wheel. Also after putting it upside down, be careful to take pictures of the nuts and washers as they are before taking them off, because they aren't symmetric between the 2 wheels.
3. Take the wheel off (the flat one) along with any parts that must come off. Remember how to put it back together.
4. Take out the inner tube by prying the outer tube off with a prying tool (a chisel can work too). Start from the side opposite the valve, because it's easier.
5. Put the new inner tube in and put everything back. Make sure the valve on the inner tube is coming straight through the hole, not at an angle (I got a hole in the inner tube at the valve once by putting it at an angle, causing the wheel to cut the valve).

Patching: If you're on a trip and don't have a spare inner tube but have a patch, you can do the following steps instead of simply putting in the new inner tube. Unless you're on a trip or something, patches aren't worth it because it's more likely you'll get another flat soon with a patch.

1. If you don't know where the hole is, put the inner tube in water and watch for bubbles.
2. Put the patch over the hole.