The waiver is valid for 180 days from the date of issuance and entitles its holder to spend up to 90 days in Qatar, during either a single trip or on multiple trips.
Qatar Tourist visa is not required for citizens of Germany for a stay up to 90 days
Check with your airline in case you have connecting flights overseas as part of your journey to Qatar. It may be the case that countries you pass through en route to your destination may require a separate transit visa. Please refer to visa requirements of the specific country.