A site without logo is incompelte. In Genesis there are many ways to add logo. In some child themes if you add logo.png in the images folder it will be automatically shown as logo for your site which is simple and better. If you can edit your funtions.php you can add a option in your theme so that you can upload header image in the header region of your genesis theme of your desired height and width. Here I am explaining another procedure which is quite simple and no need to login into your cpanel.
#1. Go to Dashboard->Genesis->Theme Settings.
#2. Once you created a child theme. Go to Dashboard->Editor->functions.php add the below line
add_theme_support( 'genesis-custom-header',array( 'width' => 960, 'height' => 100 ) );
If you want to have a custom image of custom height and width just change the width and height option accordingly.
#3. Now you will see Header under your Appearance as shown in the below figure
#4. Click on header and upload your header image size 960X100 which contains logo to left most of image.