Requirements for employment relationship

In the beginning of starting an employment contract in Germany there are a number of questions that need to be answered and clarified before you can start working. 

First of all you need an employment contract. Once you have it you need to take care of several administrative steps. 

The following steps need to be done to start employment in Germany (there is no order that you need to be aware of): 

1. Working visa/ residence permit for Germany
2. Address in Germany 
3. German health insurance (you need to insure yourself at a health insurance e.g. Techniker Krankenkasse https://www.tk.de/en , Barmer GEK https://www.barmer.de/en , hkk https://www.hkk.de/english-information or you can also find a list of all health insurances here: https://www.krankenkassen.de/gesetzliche-krankenkassen/krankenkassen-liste/)
4. German bank account (that you can receive your salary). This bank account can be opened with every bank in Germany. 
5. Social Security Number. It is not necessary to apply for a social security insurance number, as it is automatically sent to the insured person as soon as he or she starts an employment, that is subject to social insurance contributions. More information you can find here: https://allaboutberlin.com/guides/german-versicherungsnummer 
6. Identification Number/ pension insurance number. The identification number is assigned to every person whose main or sole residence is recorded in a register of residents in Germany. Persons who are not registered in a population register but are liable to pay tax in Germany also receive a tax identification number. It remains valid for life and does not change even if you move or get married. The tax identification number is a "non-speaking number". This means that neither personal data nor the responsible tax office can be read from it. The identification number is administered by the Federal Central Tax Office (BZSt). More information you can find here: https://service.berlin.de/dienstleistung/329123/ 

All the above is needed to start your employment. But do not hesitate to ask for help. Your employer is happy to support you.