For complete beginners?
The only complete grammaire is Mallon's, and it is a reference grammar. Do you read French? (there is an Arabic translation, but I don't know how easy it is to get-there is an incomplete pdf somewhere on line. The French is on Google books).
I don't know French. My Father and Teta know fluent French, though. They might be able to help me put.
Fwiw, a friend of mine from Tasbeha.org recommended "So You Want To Learn Coptic" by Sameh Younan and "A Study in Bohairic Coptic" by Nabil Mattar.