He just said... put the bass way up.
If you want a more metal sound usually you want to drop the mids out ("scoop" them) and bring your bass and treble up. I would suggest trying something like B: 5 M: 2 T: 4 and see how that sounds.
It is going to be different between every amp and like wise every speaker you put in the amp and every guitar you plug into it. You should just play around with it and listen to what happens. Soon you will start to recognize what you need to do to the knobs to get the sound you are looking for with out having to ask. You will know what it will start to sound like if you turn the bass down for instance.
I like mids, so even when I play metal I tend to have the mids up a lot more, but if you want a really dark bottom heavy sound then turn the bass up and the mids down, then adjust the treble till you get the amount of bite that you like. I like a lot of bite. But to much treb will make it sound screechy ad ugly. too little treb and your guitar will sound thin and quiet when you aren't chugging away on the low e string. This will also happen if you turn down the mids too much.
The point is we don't know what you should do. Listen to your ear and let it tell you were to set the dials.
