How can I change site title "Frank Bow" 's color or replace it with a Logo Image?

If you want to change it by logo, please go to

Admin Panel > Options > Header Options

You can upload your logo there.

To change color, you can edit the code in:

Admin Panel > Appearance > Editor

Find Section: Header , then add this code:

.header .site-title a {
color: red;
}

The color is up to you.