In the default theme that I have chosen to modify for the Forum, you may click on the TIGHAR logo in the upper-left corner of any page to return to the homepage, https://tighar.org (https://tighar.org/).
If you modify your profile to use a different theme, you will have to find your way to the home page using your normal methods for visiting the site.
If you have a favorite SMF theme you want me to install for the site, let me know. Some seem to work better than others, as far as I can tell.
We are currently using version 2.1.4, so the theme you want to have installed must be compatible with 2.1.