Use Generate press to control colors and layout. It is super easy.
No need to use it as a page builder. It is weak in this area and there are better choices, notably Elementor.
Activate GeneratePress Premium – Colors
GeneratePress Premium Colors let you choose the colors for many components on the page
Activage Generate Press Premiums – Spacings
This allows finer control over padding around the title image, the height of menu bars, the spacing between widgets, the width of the widget bars.
Do NOT activate Generate Press Premium Sections
Generate Press Premium Sections is their version of a page builder, allowing for titles above content. The problem is that this is not WYSIWYG like Elementor. Also, it does not allow for columns and the richer structure of Elementor.
Do NOT activate the other parts of Generate Press Premium
These are not suitable for our purposes