This provider lists TER as being an accepted screening service

I think she is talking about having whitelists from providers that you have seen before   That is the only way of screening that I know of.  I hope that helps.

What are whitelists?
What if my providers are not interested in providing whitelists for me?
I am new to the hobby and have only been to one provider multiple times.  She is very cautious and I suspect would not be interested in going online to do anything.

...the rest is just getting references... my recommendation is this:
Find yourself one or more of the many "newbie friendly" providers that regularly post here. I'm sure someone will float your boat Book a session, then ask them to Whitelist you afterwards.
Unless your a real jerk, most will oblige you.