Sub-To experts! Contract advice needed

[Heather Watkins]

Sub-To Experts, 

I have someone who is willing to do a subject-to agreement with me and I am wondering if anyone one here has experience with sub-tos, possibly an agreement/contract template you wouldn't mind sharing, and all of the next steps so I don't miss anything. 

I am totally new to creative financing. I did try to look up some resources on here and couldn't quite find what I was looking for. 

Thank you in advance!