Welcome to the forum.
There are some sports oriented photographers that stop by now and then that may give you better tips.
You did not mention your photography background, so please forgive me if I say something you already know.
Practice. Practice. Practice. Your son might be happy to indulge this 😀.
Set the lens to auto focus and for now, concentrate on the three basic parts, shutter speed, aperture and ISO. Set the ISO around 800 to 1600. This may seem too bright for a sunny day, but it will give you room to use the aperture and shutter speed without the scene getting dark. If the lighting is darker, use ISO 1600 to 6400.
Set the f-stop on the lens to around 5.6, this should give you enough depth of field (the sharp in focus part) to get his face and most of his bike — this will also depend on how close you are to him — while blurring some of the backgound. As you get used to what this aperture does at the distance you are from him, try other settings, wide open (the smallest f-stop number) can give you very pleasing results as can f16. Remember you are focusing on him, not taking landscape photos, so the background blurring is going to be different.
And the last part, shutter speed. Start around 1/400. The higher the shutter speed, the less motion blurring you get and the more the foreground will seem in focus. This is why you need the higher ISO, because higher shutter speeds will make the image go very dark. Try a bunch of the speeds. There is an art to getting the right blurring for the shot, from none at all to massively blurred.
Then back to the practice part.
After this, those other things on your camera are there to give you options in your approaches. You might set Auto ISO up so you can concentrate on shutter speed without worrying what rapidly changing sky clouds are doing to the images. Or how to use the back lcd as a focus aid, etc. Bring in these new options in a few at a time. Oh yeah, take the lens off auto focus mode and see how you like that, it does work.