When you receive your tulle veil carefully take it out of the box and hang it up. Make sure to put the veil back in the bag to keep it from getting dusty. Hang it in a dark place out of the sun and away from animals like in a closet. In my studio, we use clothes pins to hold the comb to the hanger (we also have thin hangers). Long veils will need to hang from a high spot or can be folded over a hanger.
To remove wrinkles you can get your veil pressed at a professional dry cleaners. I do not recommend using a steamer as they can be too hot and melt the tulle. The easiest way to 'steam' your veil is to just hang it up (out of the bag) in the bathroom (not in the shower) and turn the shower on full heat and let the bathroom steam up. The steam from the shower will get most if not all the wrinkles out. Do this for about 10 mins or longer for more stubborn wrinkles. You can hand smooth any stubborn wrinkles as well and let it steam a little longer if needed. Super easy! A little water will not harm your veil.
If you have a silk tulle veil I recommend getting your veil professionally pressed by a business that is familiar with working with silk tulle.
Also make sure the area around your veil is clean if it needs to drape on the floor :)