I got a bit confused between the minimum number of questions required to start a site. when I propose a site I need to have 5 questions but to get the proposal (defined) I need at least 40 question with 10 votes! what is the difference between those two type of questions ?!
They're just different milestones to get through the process.
After the proposal has been submitted, you have three days to get the proposal off the ground by submitting (or attracting) 5 example questions and finding 5 or more users who are willing to 'follow' the proposal.
Once the proposal gets going, you will need 60 followers and 40 example questions with a vote of 10 or more to move to the next phase (Commitment).