I provided them with a FAX back form immediately after I deposited. Since I used my debit card I sent them copies of the front and back of the card and address verification and copy of my drivers license.
Their fax back form can be found
here. What I like about their form is you can fill it out online then print it, sign it, scan it and email it back with the required docs. I keep a zip file of my docs so I can just copy them into another zip file along with the forms if necessary.