Honda 200atc electrical modifications

Hello, all I have an 83 200atc that is just the base module so no electrical start no battery ect. I use it mainly for ice fishing, I want to add an led flood light to the bike. So my question is how do I add a battery to the electrical system to run the led lights and also have it charged from the engine running? This has to be possible but I’m just a little confused as to that parts are needed and how it would work. Thank you in advance!