First is a phone interview where you are asked a few standard questions. Here the owner is trying to figure out what kind of person you are. Why you want to work for him. Mostly questions about your interests and questions about your resume.
If he likes what he hears he will get back to you and invite you to come in for a technical interview. He will tell you about two phones that he will have you tested on. To prepare for the interview you are supposed to find and watch some disassembly videos on youtube for the phones he assigns you.
The day you arrive for the technical interview you will be put work right away. One of the other techs will time you and assist you with any questions during the test. If you did your homework you should do pretty good. Just as important as doing well here, you need to have a good attitude and convince the owner that your personality will fit with the rest of the team.