Don't. No matter how many ways there are to use the dawn of war references, the odds of you drinking the basket are 1000 to 1.
But if you want to ignore Librarian's advice and you are still thrilled by a thought to impress a crush by warhammer references, go to the Step 2.

(Preferably after a workout, but not necessary) pass by her while rapping song "The Emperor's Light" (try to rap this song in a way that testosterone screams from you), hopefully she will chuckle and maybe cringe at the same time while you memorise entirety of this article[wh40k.lexicanum.com] about space marines, while later you explain to her who is Vance MF Stubbs and how he lost 100 mf baneblades.

Try to take phone or any device at hand where you can open youtube, and watch some dawn of war gameplay or in-depth lore about warhammer, hopefully if she is bored she will ask you what is that you are watching and you will be ready to explain to her how you drained over 1000 hours in these games purging heretics without looking like a degenerate.

Since warhammer lore is really huge and she could be dead by the time not even explaning every single space marine chapter, you should come up with some warhammer memes. Who doesn't like memes, right?

By the time she should already know that you like warhammer, and since she know very little about it, you should immediately start making your space marine costume for halloween to impress her, a couple months before halloween go to the non-legal gun maker and ask him to make you and teach you how to use a bolter and a power sword.

Since you werent at the home a couple of months, she might be asking what is going on with you and where did you disappeared?
That's the neat part, you blow up on halloween party in your based space marine costume with skills of using power sword and a bolter (which they will think is also a costume), and you slice or shot in the head anyone who insults you (if you played dawn of war 3 everyone will bully you at the party because you are a GIGACHAD).

After the halloween she is all wet because of your chadness, this is your 5 minutes, go talk to her and try to develop a friendship with her on a higher level, ask her if she likes warhammer, if the response is positive, you're in, if not, try to convince her otherwise, show her more of warhammer you think she would like.

Later on she will get every of your references and start searching for more of them, try to convince her in getting to the dawn of war as well.

If you ever get to the level of having s*x intercourse with her, after the foreplay and before the main part where you need to insert your machine spirit in her Speranza you will need to pay a tribute to a Indrick Boreale and recite his final speech like he did to his fellow brothers Blood Ravens, and when she hears the "SPAHSS MAHRINES TODAY DI ENEMAY IS AT OAR DOAAR", she will likely get up and run out from your apartment, and since she didnt let you finish your tribute to the INDRICK BOREALE, you will know that she was all for the streets.
Although if she don't mind your degenerous behaviour and still wants you, then my brotha you have a keeper there (or she is just retarded).

Okay so this is it, she likes you through the warhammer references and she likes the universe.
Its a win-win, one for you, and one for the EMPERAH!