You need to set up your own PAYE and NIC scheme which you will operate on behalf of your German employer. In the notes under "Business in the UK treated as employer" here, it says that as your employer is an EU employer, it will be treated as a UK based employer. Either it or you will need to operate a PAYE/NIC scheme. If you move towards the bottom of the page and look under "Employee has to operate own Class 1 National Insurance", you will see there are notes on a PAYE and NIC scheme (DPNI) which is what you need to set up. Call the number here for further information and guidance on getting a scheme set up.
I hope this helps but let me know if you have any further questions.
I have to go out for a while but will be back a bit later to answer any follow up questions that you may have.
Hi.I'm just following up to find out if my answer helped or if you have any further questions.