There are two ways to link an element to another page.
Option 1: Use the toolbox
First, double-click any element to open the toolbox with editing options.
Click "Link to Page" to open a menu that shows you available pages in the project.
Select a page to create the link. A little blue icon will appear in the upper left corner of the linked element. In preview mode you can follow the link by clicking anywhere on the element, but note that in edit mode you have to click the blue icon to follow the link.
How to link to individual parts of an element
Some elements, like button bars or lists, are made up of multiple subelements. With a button bar, for example, you want to able to link to the individual buttons instead of the button bar as a whole. To do this, double-click the element as usual:
Note that the first element will get a blue highlight. This is the element you're currently linking.
Now, choose a page in the linking menu and note the blue link icon in the upper left of the element that shows the link has been created:
You can click on any of the other elements to select them and follow the same linking process.
Option 2: Drag and drop from pages panel
If you prefer, you can use the pages panel to drag and drop pages onto elements to create links. First, open the pages panel.
Click and drag the page you want to link to on top of the element that should be linked. The element will highlight in blue to indicate the page can be dropped.
Once you release the mouse and drop the page on the element, the link will be created.