Here's a link that should take you to the community using whatever instance you're signed in with:

[email protected]

Normally, to do this you just type ! and then start typing the name of the community, then select the right one from the dropdown list. Unfortunately the current Lemmy software has a bug that formats it incorrectly.

This post: https://lemmy.sdf.org/post/36299

Explains how to fix the formatting, but it SHOULD be fixed in the code soon.