To subscribe to a remote community, first find that community via Lemmy Community Broswer and click on symbol to copy the link.

On TasLem, click on the search magnifying glass and paste the URL you copied into the search field. Click search.

At the moment nothing will appear in the search results (possibly a Lemmy bug), but after about 10 seconds if you click back on “Communities” and select “All” - you should see the new community in the list.

From there you can click on “subscribe” to do that, or the name of the community to view it.