Approved NIC2 payments, but how to pay from a foreign country?

Hi, i've been told by HMRC i can contribute going forward to NIC2 while living and working abroad by making annual payments, however, I have no information on how, how much, or when to pay annually? please advise

Hi 
If you wish to apply to pay voluntary National Insurance contributions whilst overseas then complete and return our CF83 application form which is at the back of
leaflet NI38 ‘Social Security Abroad’.  
You may find this via:  Social Security abroad: NI38
Before applying to pay voluntary contributions you may wish to obtain a State Pension Forecast to check your current and future entitlement to a UK State Pension.  
You may obtain this via:  Check your State Pension forecast
Thank you.