Template packs are themed sets of page templates and blocks which are created in the same design scheme.
A page template is a pre-designed, custom set of layout options used to change the way one or more pages appears. This includes things like the formatting and layout of the content as it appears on the page.
Blocks are pre-designed section templates that can be easily combined to create a complete & beautiful page. Think of Blocks like Lego bricks. You pick the relevant blocks – start with the banner, services, categories and the other parts of your page, then customize each one to make it fit your website.