Doesn't happen often but not sure Mars has got it right this time: I wouldn't leave it for later.
Too often I've listened to colleagues moan about how they know they're not getting as much as they deserve, etc. etc., and how they'll just wait for the next career discussion, or the next 6 months, or the next this, that and the other. And on the other hand I've seen others just do something about it: go to their boss or counsellor or whoever and say, "I think I should get more for this and this reason". Don't think there is a downside to doing this. At least you know where you stand, and so does your boss.
If they say no, you know, and can consider your options fully informed. If they say "maybe later", dito.
The upside is that if they do value you they might do something about it.
But for goodness sake don't wallow in it for the next 12 months and subject your mates / colleagues to yet more moaning.
And as to your actual question "how?": hard to say since you didn't tell us size / type of firm. But in general, you need to identify someone with authority to do something about it. Don't ask HR since they'll say no. If your consellor is not very senior, perhaps book a slot in your department head's calendar, and prepare your case (market salaries, your contribution to date, your ratings, chargeability, your career trajectory, etc.). And know how to respond to the question: "so how much do you want / think you're worth?")
PS. "toe" not "tow" (little bugbear of mine)