You need to be a member of HHonors first and select HHonors Points plus Fixed Miles as your earnings option and bmi as your airline.
Then as stated you need to register for the promotion:
Originally Posted by
NewbieRunner
Then you need to book via Hilton:
Originally Posted by
nalle
Book your stay with Hilton. - Hilton.com or the hotel itself, then you can earn points + miles. - Remember your Airlines number and show it at check in, then you will automatically get double points.
Or rather, your HHonors account will show that you have earned double points. However, in all likelhood you will be waiting forever and a day for them to show up in your DC account. If you need them in a hurry you will probably have to chase them.
You can only collect a maximum of three nights of points per stay (i.e. 6000 miles per stay during this promotion). If you are staying longer or very regularly I would consider carefully how you register for this promotion. Once you have an HHonors account you also have the option of collecting double HHonors points for hotel rooms, which in some cases will be better value (especially if you are staying at expensive hotels).