I don't know how to activate my DQ ring.Can you help me?

You've already activated your DQ ring.
Is the problem the fact that it won't show up in-game?

Oh, yeah.That's the problem

There are a two basic ways in having your item(s) appear even after you've activated them.

1) Go in-game and type /dl BloodMach. Wait for it to say "Download Complete" in the chatlines, and then type /lp 0 BloodMach. This is the easiest and fastest way to solve your problem.

2) If you didn't feel like typing in those commands, simply go onto multiplayer and play a few games. Your item should show up after 2 games or so.