I admit that im sort of knew to this genre as well, but ive been getting into some hardcore punk lately (early Black Flag, Minor Threat, Discharge, etc), so im familiar with the sound. Discharge have been credited with starting the crust punk movement, so they are a good band to start with. The album Hear Nothing See Nothing Say Nothing is supposed to be the precursor album to the crust punk movement.
I would probably describe the crust sound to be bassy and dirty sounding hardcore punk. It is still rough around the edges like punk, but can have slower heavy metal like sections and song structures (resulting in longer songs). You said you like Amebix, and imo I think their album Arise! is a pretty good example of pure crust (also check out Antisect, Doom). The crust genre is basically the combination of hardcore punk and metal, in varying degrees. Later Darkthrone is considered crust, for instance. It's all got a certain sound to it, which im sure you will figure out soon.
Some crust albums ive been enjoying lately are Axegrinder's Rise of the Serpent Men, and Deviated Instinct's Welcome to the Orgy.