I recommend searching the web for info on ISO 17025. There is a lot of good info available online.
I attended an ISO/IEC Standards 17020/17025 training course sponsered by ICBO ES (now the ICC ES) and proctored by IANZ two years ago, very informative, very professional. Participation by attendees was encouraged. Certificates are issued to all who attend and another for the exam at the end of each session. I understand passing rate for the exams are about 30 - 40%. (I did pass both exams.)
I think the $ spent is well worth the knowledge gained.