To access the advance Frontpage sections and other theme features, you need to install and activate this plugin. After that, you can see the homepage sections like the Service section, Funfact section, Project section, and Testimonial section. For the Pro version, you are not required to install this plugin instead when you switch from lite to pro you have to disable this plugin.
To add a contact form, you need to install and activate this plugin. After that, create a contact form by using this plugin and use the shortcode of the form on the page editor.
These plugins are not mandatory for the theme to work. If you want to use all the features of Quality please install and activate those plugins. After this, set up your front page.