If you have no air in your tyre and it’s not sat on the rim. When you go to inflate it, the air is just going to leak out…
This video shows you how to seat the tire on the rim and create a seal so you can inflate it. I’m going to use a foot pump to demonstrate. As this is probably the most difficult way to do it, as you don’t have a constant flow of air.
Note:
Check the air pressure after a few hours, (and then a few days later) to make sure there are no leaks.
More detailed information can be found on this page: How to Replace a Wheel Valve Stem: (Opens in a new window / tab)