How does one start lending private money?

I have about 50k that is just sitting around, and I don't feel comfortable putting it in the stock market and I would like to get a higher return than 3% or so from a high interest savings.

I am wondering how hard it would be to become a private lender to build up some more capital before I start buying more rehabs.

What is involved as far as overhead, legal requirements, etc.etc.

Any input is appreciated.

Thanks
-terry