Hi,
1. Please create brand as attribute http://take.ms/sprpk
2. Go to Appearance > Widgets > add YITH Ajax Filter Widget and select brand as label http://take.ms/eo575
3. Config for size like this http://take.ms/XLKd1q
4. As your screen shot, the brand now is product categories, it can’t display square like filter bar. You can change background image for category by edit this category and upload thumbnail image.
If you want change color please add custom css in Claue > Theme Option > General Layout > Custom CSS
.page-head:before {background: #555;}
Change #555 with your color
Best regards
Harry
Premium Wordpress themes and plugins, Best WooCommerce theme https://themeforest.net/user/janstudio/portfolio?ref=janstudio