Private Seller lead - South Texas

[Diego Alvarez]

I have a potential private seller with a good deal in hand however I am not sure what next steps to take. I dont have the 20% down so I am looking for a partner but how do make sure I am doing the right things needed to : 

1. secure the sale

2. I dont get screwed over by a partner. 

What would you do in this situation?

Any resources recommended to get more knowledge in this space? thanks!  

In addition, where could I offer a deal? I understand biggerpockets doesnt allow it here.