Briefly, your husband has been summoned to immigration court, and though he has some time to prepare, you should take all your paperwork to an attorney as soon as possible to find out our options. The court should have sent you a list of free or low cost legal service providers, but they cannot take every case -- so the sooner you get in contact with someone on the list, the better. Here are a few links where you can start your search for an attorney.
The Department of Homeland Security initiated deportation proceedings against your husband. The Notice to Appear is the charging document used to initiate the proceedings. As it was filed without a hearing date, time and place, the immigration court will issue your husband a Notice of Hearing addressing those deficiencies. If your husband changes address, it is his responsibility to notify both USCIS and the Immigration Court. If your husband fails to appear, he can be ordered deported in his absence.
The Master Calendar hearing is a preliminary hearing. The judge will determine if your husband has received the Notice to Appear and if he understands the charges. The judge will inform your husband of his rights in proceedings including his right to an attorney. The judge will likely want him to enter pleadings to the charges.
Please consult with an immigration attorney who is skilled in deportation cases. Missteps at any juncture can substantially impact a foreign nationals ability to remain in the country.