How to use zoom without webcam? Show photo instead? Account required?

Sorry for these newbie questions. I am new to Zoom.

I want to run Zoom from my desktop computer which has no WebCam.

Is it possible to participate in a Zoom meeting anyway?

I got an invitation link form someone else.

Can I show a photo instead of the webcam live view?

Where in Zoom do I have to upload/specify this default photo?

When I start zoom (on Win10) then I am requested to either"Join a meeting" or "Sign in".

Assume I want to Join a meeting (created by someone else) do I have to sign in first or is this possible WITHOUT an existing Zoom account?

Is there a dummy Test Zoom meeting (provided by Zoom) which I can use to test the zoom meeting handling?

Thank you

Thomas