How to get started? Company provides Retirement Plan

Starting to dip my toes in to investing and I don’t know where to start. My company provides a retirement plan and acct with Fidelity. I haven’t looked much into it because I’m not sure I will stay with them, but from what I understand they provide a decent IRA match.

If I want to start investing do I need to open a separate brokerage account? If so, any recommendations?

Also, any advice as to which initial investment would me much appreciated. I’m a part time worker so I’ll only be investing a little at a time.