How can knowing common first aid skills prevent infection and facilitate the healing process

When you know the common skills to use a first aid kit, you can prevent some minor damage and hopefully prevent the worst from happening. For example, if you scraped a knee, badly, and your mum knew how to deal with it, by cleaning it properly and bandaging it up properly, she's preventing you from getting infection, from not cleaning it nor protecting it from the outside world, you would most likely contract an infection, and it's best to not go with that option, it also helps to know common first aid kit skills if you cannot seek professional medical attention right away.