Adding header and customize landing page when using a theme

Hello all,

I've applied the Dalvar (and other) themes and cannot figure out how/where to edit header, login page, or add logo.

Please advise or direct me.  I haven't figured out how to search discussions in this forum either yet, so looking for similar questions hasn't helped.

Thanks so much for any/all responses!

Beginning Developers

Beginning Developers

This space is for newcomers, who wish to build a new plugin or to customize an existing one to their liking