In Country, In Trouble, Incapable ?

You've figured out all the personal and professional reasons why working overseas is a wise move.  Now you need to get settled, get registered, and get ready.   You have period of several days where you will be torn between personal and business obligations.   You'll likely want to impress your employer during the first few weeks but also have a focus on getting your personal life in order.  This involves work permits, driver license, resident permit, health insurance, bank accounts, and many other German agencies.   If you have kids, this can be a tense several weeks.   I'd make three recommendations.

1) Give yourself 5 days in country to get paperwork processed, visit needed agencies, get unpacked, explore some of your surroundings.  
2) Your employer MUST assign someone to assist you with all the necessary documents.  There are lines in all these agency offices.  If you get it wrong, it's back of the line.  Many agencies open from 8am-1pm only.  The translation assistance is critical for time and your emotional state. 
3) Bring your personal file with you.  This includes all the passports, birth certificate, marriage licence, drivers license, letter of employment.  

I recall there was a sequence of visits to get through all German agencies effectively.   It goes like this..

- Get a formal letter from your German employer (Arbeitsbescheinigung) stating your employment start date and title.  Get is signed and stamped by a senior official in the company.   Everything requires a stamp!
- Take that letter to your local bank and set up an account.   You'll need a passport and a small deposit but this will get you started.    Bring this account information to your employer.  Keep the BLZ# and Account#.
- Visit the ArbeitAmt (Employment Office) and you need to get Application for Work (Antrag auf Arbeitserlaubnis).  Complete them with your employeer, have them stamp it and sign.  Bring all forms, employment letter, passport, bank account and visit the agency.  This is a two-year stamp so you'll need to keep copies of this paperwork. 
- Visit your BergerAmt and complete the Application for Residence Permit.  This will require passports once again and they will be stampted.   Before your departure from your home town, ask for an official (stamped!) letter stating you have no criminal record, warrants or infractions with the local Police Dept.  It will likely be used during this visit. 
- Visit agency for KinderGeld (if you have children) and register for this stipend.  This allows for added income for care and feeding of the children.  They deposit this in your bank account directly. 

Bring several additional passport size photos of yourself.  These will be attached to various files for German agencies.  Start early with the process, get your employer to provide assistance, be prepared to visit some agency offices more than once.   Take a deep breath and relax for it will be over soon.