I am online with my course since approx. 2 weeks, but my traffic is just about 12 people in 2 weeks. Will the traffic increase and Udemy help to push it beside my own recruiting for new visitors? (e.g. with affiliate links, etc.)?
yes, sales are likely to increase over time. However, success of a course depends on multiple factors like popularity of topic, number of competitors, success of other courses covering the same topic, length, contents, keywords and marketing.
To make Udemy promote your course, you must opt in to the marketing program. Success of ads etc will also depend on the factors listed above.