I’ve heard going very slow pace at first is important. You start to use new muscles and stress yourself in new ways so you need to take it easy until you begin to adapt. If you go fast/fastish too early you can cause damage or get splints I think. Something along the lines of pace as slow as a walker and move to higher speed at you own pace.

Hey I’m not trying to be an ass as everyone has a right to contribute but you really didn’t answer the ELI5 question. You just slandered some groups or something