I've downloaded the dashboard, but can't always find it.

I've downloaded the dashboard, but can't always find it. I downloaded the video on installing a theme...but, I see in notepad instructions. I registered my domain on dashboard? but can't find it to get back to again - to I guess, proceed with embedding code from the instructions to a new post, etc. in order to view video. I just want to get a theme (Scribe) installed so I can start working on it.
Obviously, I am missing a step or two...please help. Thanks.