Ypu can pay an agency which ia super expensive or you can get a certificate of residency fron immigration (if you are renting you need rental agreement) once you have this you can do teat yourself. You need a medical certificate as well
The police check was easy enough. Its just making surr you have the paperwork in place before you go. For me i had to take a letter of intent so they knew it was for a teachers role. Yours will likely differ but that's where my help runs out. Sorry.