As a male who previously worked customer service for feminine care products, I think I might be able to provide some advice here.
Get familiar with the different feminine hygiene brands. Assuming you are in the US, that's Kotex, Always, Stayfree, Tampax, Playtex, etc. Don't just assume that having the talk is the end of it. There will be an adjustment period (no pun intended) as the daughter gets accustomed to wearing pads and finding which one works best for her flow needs. In the meantime, there may be some embarrassing leakage incidents which will need to be handled with understanding and maturity. Don't make this any harder than it already is for her. If he's the primary launderer as well, make sure that he can identify and properly launder the staining and adhesive residue that will likely occur with some of her clothing during this process.
Spend some time in the feminine care aisle. Understand the difference between the different products. You're probably going to end up in this aisle trying to find the one product your daughter says that "works", and it isn't fun to get back from the store with the wrong ones.
The internet is your friend here. In addition to lots of product information, some feminine care product websites like Always and Kotex brands also contain information about different women's health issues like menstruation, body changes during puberty, as well as suggestions for parents that are bringing up the subject for the first time with their daughter. Some of this information is printable so you can use hand it directly to the daughter and allow her to read it at her own pace. The Kotex site also has period planners and message boards for asking questions that the girl isn't comfortable enough asking face-to-face.
If the internet isn't your thing, pick up the phone and call the consumer services departments of these companies directly. There are people there whose sole purpose is to make you feel comfortable with choosing, buying and using feminine care products.
Don't try to do it alone. There are people around that would be happy to help.