You are exactly where I was when I got mine.. I hated it till I figured it out. First thing to do is hook it up to a pc with hd edit and download some patches/sounds.. The big flaw in these hd models imo is the 400/500 are not compatible.. so the 300 sounds that are uploaded are weak.. I can't even find a randy rhodes sound ffs.. hes like the king of rock/metal..
Also, if you're trying to adjust settings on the board itself, I advise against that.. You can but its such a pain in the lollipop.. just use HD edit, load up any preloaded sound are just start tweaking.. What band/sound do you want? The 300 is very limited in my opinion.. You can only get 3 effects and a reverb and you can't even get flanger and chorus at the same time as they are in the same effect 2.. so its either or, not both.
I should probably upload a complete noob video or something because I played acoustic guitar for like 20 years and had no clue about electrics or the gear and trying to figure this pod 300 out was like pulling teeth.. I didn't even use it after the first week of messing around with it till about 2 months later thats how much I hated it and my line 6 spider 2 1 12 had a better metal sound that I could get out of that board back then till I learned how to use the thing.. and even now Im not a pro at it yet.. Just watch and read a lot about it, you'll pick up how to use it easy.. I actually came here to lollipop about the stupid thing not being able to get a decent randy rhodes sound and a lot has to do with the 3 effect limit and certain effects can't be used at the same time.. Or maybe Im missing something..