Assistance with private lending question

[Toby Jurging]

Hello, I will be funding (lending) purchase and reno on flip project, second with same partners.  Honestly, the first one was more of a handshake deal, plus I purchased the home and had it in case things went south.  In this case I am just funding and would appreciate any assistance with how to go about securing 1st position/lein on mortgage in case of negative situation.  

Promissory note will spell out terms, etc, does this constitute my position or is/are there additional steps/forms needed.

Thank you