In Germany, it's important to be serious in a work situation. They don't mix work and play so you shouldn't make jokes (1) you do in the UK and USA when you first meet people. They work in a very organized way and prefer to do one thing at a time. They don't like interruptions or (2) changes of schedule. Punctuality is very important so you should arrive on time for appointments. At meeting, it’s important to follow the agenda and not interrupt (3) speaker. If you give a presentation, you should focus (4) facts and technical information
and the quality of your company's products. You should also prepare well, as they may ask a lot of questions. Colleagues normally use the family names, and title - for example 'Doctor' or 'Professor', so you shouldn't use first names (5) a person asks you to.