You are safer adding it via TSQL. You need to run sp_addarticle and sp_addsubscription. Then you need to run the snapshot agent.

Sp_addarticle adds the table to the publication. At this point nothing happens as the subscribers aren't aware of it

Sp_addsubscription adds the new article to the subscribers. This can apply to all subscribers or you can be granular and run it for single articles and subscribers.

The snapshot agent will generate the schema script and bcp the data of ONLY the new article.