Okay im brand new to playing, i have a basic Yamaha AK15G amp that came with my ERF121C

The problem is, i dont really know exactly what im doing when i mess around with the knobs.

On my guitar i have 5 settings for my pickup selector, humbucker - inbetween - single coil - in beteen - humbucker

Plus the tone and volume knob.

And then for my amp, i have an Overdrive knob, "clean volume", Treble and Bass.

Now i cant even hear any noticeable difference turning the overdrive knob, as long as the button is on.
theyre are two "modes" on your amp, a main (clean) mode and an overdrive (dirty) mode. there is a volume for each one of these so when you are on clean and you turn distorted up nothing will happen. oh and welcome to guitaristisiam have fun and practice every day. good luck
Obviously i know that, but i mean when distortion is turned on even if overdrive is at 1 or 10 it still sounds the same.
Does it work when you have the button pushed the other way? When the overdrive knob works, you're on the overdrive channel. When it doesn't, you're on clean.

The volume on your guitar is pretty simple, it lowers volume when turned down. The tone control rolls off the higher frequencies of your sound as you turn it down.

The treble and bass knobs on your guitar are collectively called the EQ section. It stands for equalization. The treble knob controls the amount of high frequencies, and the bass controls the amount of lows. Some amps have a middle control which, obviously, controls the middlin frequencies.