Take note of the visa’s expiration date and the number of entries permitted. Within this time window, you must depart the country.
Keep a copy of your passport and other travel documents with you while travelling within the country. You must have your passport and visa with you if you are travelling to another Schengen country.
While on a business permit, you are not permitted to engage in any work-related activities.
You won’t be able to extend the permit unless there are exceptional, unforeseeable circumstances, such as force majeure, an undesirable situation in your own nation, or something similar.