When to collect the option fee in a L/O deal

[Tiffany Grace]

Hi, I'm working in my first lease option deal. I am holding an open house this Saturday,  and I'll have the applications there as well as property description sheets. I just wanted to know when I find a qualified buyer and they've completed an application and have already saw the house when do I collect the Option fee, and do I set up an appointment with the real estate attorney to sign the lease and have them pay the option fee there? What if they present the Option fee to me? Do I just give them a receipt and take the money to the attorney's office at our appointment? I'm just getting a little hung up on this. I also wanted to know if any of you have your tenants complete a questionnaire to get an idea if they would qualify before you have them view the house or complete an application. Jist trying to get these steps clarified. 

Any tips and advice is appreciated. 

Thanks!