Admin and front-end
Your website is splitted in two areas: administration and front-end, the administration is the area where you crete the pages, the menu and where you insert all the contents of your website. The front-end is the final website that see the users and is the result of the admin contents. You will build your website in administration area and you will see the result on front-end area.
Build your website - basic instructions
You can build your website by use only two components: the pages of your website and the menu. The pages of your website are at WordPress menu > Pages, you can edit them click on the title, for see the final result (the front-end) click on Preview button on right (or on top). If the changes are correct and the pages show good you must save it by click on Update button on right (or Save changes on top)
Build or edit a page - basic instructions
All the pages of your website are a combination of components like texts, images, videos and more. When you are into the administration of a page you can see the icons that allow you to add new components. You will build your pages by add these components and by insert the contents you want into these components.