Quad biking 101 for my son

[Akay17]

Hey, I’m new here so hoping you can all help. Although I grew up in a family of bikers, an accident when I was younger resulted in me not learning to ride a bike, or basically anything about them. My dad, step mum, mum and brother all ride, and are very helpful but looking for a fresh set of opinions, as my family can be a bit one sided. My son (4 and a half) loves anything fast, so to start him off we got him an electric quad last year, which he loved, however it’s just not fast or powerful enough for what he wants it to do. My brother (lives in Australia) has now bought him a 50cc mini quad bike, which was delivered yesterday. My dads getting his mechanic to set it up and give once over for us, so I know it will be safe for him on Christmas Day. This is where I’m stumped, although they will help (in their own way) I feel like a total novice and no idea how to help teach my son to ride it and stay safe while on it. Anyone in similar position got some helpful tips here? Also what’s must have protective clothing? I’ve had a look on line and so many different ones to choose from. We will likely be over park mostly, up and down large hills and through lots of mud. 
also any tips on how I can keep my nerves settled while he’s on it, not want to scare him although want to make sure he’s safe.

thank you 

[MikeHorton]

Welcome, re quad I'd consider a few things if you are riding anywhere rather than private land with the owners permission you will need some form of Insurance, bike will need to be registered. Stick to private land, plod can seize your new bike otherwise. Re kit you will need to go somewhere where you can try it on as he's a young lad. I'm sure there must be clubs out there which would help as you need to make sure of safety ideally some sort of Marshalled course with first aid provisions. Personally 4 seems too young but maybe do some local research to keep safe if your gonna do that