Ask HN: Where to sell my startup shares?

Hi HN, I am working at at startup. I now want to cash out part of the shares I own from this startup, which represents interesting money.

I found different platforms like: - https://equityzen.com - https://sharespost.com - and https://forgeglobal.com

Any experience or advice in using those platforms or others? There's very few information on how to sell startup shares.

Thanks.