First Flip - Borrowing Questions

[Liam Morris]

Planning to do our first flip in the next couple weeks.

Taking an unsecured loan from the bank, savings, and borrowing money from 1-2 friends.

What advice do you have for making sure the friends’ investments are secure and safe? I was thinking of filing a primary lien on the property to secure their investment (hard money - interest deferred format). Anyone have recommendation on forms or process of doing this?