The position was referred by my friends. The best way was to prepare enough before the interview day. The interview had two parts, the 1st part was that the store manger asked "tell me about yourself"question, this question tested how your english proficiency was and understanding what's your background, eg some education or experience before, and also you were asked some case problem such as how to deal with difficult customers. The 2nd part was to meet IT manager, you were given a PC machine and asked what was wrong with the machine, you had to test it for finding problems then provided a troubleshooting.
The whole interview process was not long, about 30 to 40 minutes, then you were told if you got hired or not immediately. Hopefully this tip helps you guys who will apply some technical position at computing retail store.