Basically, I've just did mine last month, I changed from visit visa to family joint visa. Unfortunately, I couldnt remember those documents needed for it..because my dad's friend helped us to do those things, then later we went to the main MOI office at Madinat Khalifa to submit those documents, after that I was required to do medical check-up at the Medical Commission.. One advice from me, the whole procedure takes long time to complete. I used the one month visit visa to submit documents & wait for them to approve it, then I also extent my visit visa before it expires.

Good luck!