For registration, you have to fill out a registration form and produce your passport and visa. Registration forms are issued by both the municipal authorities located in Bremen's city centre and the campus of Bremen Service Universität (bsu). You have to enter personal information and your new address in Bremen or your interim address, as applicable. In addition, the registration form requests the name and residence information of your new landlord or the renting organisation/company. Make sure you have that information on hand when registering.
Upon completion of your registration you will receive a confirmation of registration ("Meldebestätigung"), which is printed on very thin, white copy paper. Please keep this paper in a safe place. You will need it on various occasions, e.g. when applying for a library card. Please note that you have to inform the registration office within the first week every time you change your place of residence.