Newbie needs help making first M4L audio effect

Hello all. Hope i can get some good pointers here.

I'm learning my way into M4L coding. The first audio effect i want to learn to make is a Delay that can separately delay each channel (L R) both positively and negatively. Preferably controlled by a modulator such as Modwheel.

Frankly, i don't really know where to start. I've seen the tutorials in Live so i have learned some basic principles of changing already made effect etc. But as far as coding from scratch goes i'm a newbie.

In Live's Audio Effects there are M4L Building Blocks fx. I opened the Max DelayLine.amxd and tried some things with it. I couldn't get it to do a negative delay but i understand why. To do that i would have to move the starting position of the sample forward.

It's a bit frustrating that i have in my head what needs to happen but i can't translate it into an effect yet.

Can somebody either help get me started with a small step-by-step or point me to a tutorial related to what i'm after??