If you plan on regularly riding your bike around town changing a flat is one of those skills that you must learn so you don’t get stuck in the middle of nowhere with a flat tire.
We do recommend including a spare inner tube and a CO2 cartridge in your go-to bag of tricks to make changing a flat faster. You can always patch that punctured tube when you get home. If you use CO2 deflate the tire when you get home and inflate it with your regular floor pump. CO2 quickly dissipates through the rubber (the science is here).
wikiHow as an excellent tutorial on how to change that flat tire and we would recommend you read it. twice.