Need some tear down advice

Just got my tool kit. I have a red cat 32, I'm completely new to this, but I am mechanically inclined. I want to take the wheels off and look at the hub connections and that whole area to begin with. I have a strange wobble on two wheels of the same side of the vehicle.

So my question is, do I need to know anything like tips or tricks when removing components of the vehicle, mainly the wheel and wheel area. Is holding the wheel statically when removing the I think it's a nut, nescaesy? Feels like it is.

Thanks in advance Any other tips and tricks are more than welcome