How do I vet a syndication as an investor?

[Kayla V.]

Hi all! I'm interested in passively investing in large apartment deals. I already have connections to a few operators and have browsed their packets but haven't pulled the trigger yet. 

Does anyone have any recommendations for educational resources (books, podcasts, courses, etc) for how to vet the operator and the deal itself? I understand the math but need more information on what to look out for as red flags. 

I'm seeing returns of around 18% IRR for a 5 year hold- is that in line with what most are offering?

Thanks!