Navigate to the file/folder you want to link in your resources section, and click on the three-dot menu to the right-hand side of the file name.

Click on Copy link to clipboard in the dropdown menu. This copies the link to the file, ready to be pasted elsewhere.

When creating a new article, click on the link button in the toolbar.

In the pop-up that appears, click in the URL field and paste the link to the file (right-click and select 'Paste' or press Ctrl + v or cmd + v). This will automatically fill in the Protocol field.

Fill in the Display Text field with the text you want for the link (e.g. 'Click here..').

The text will appear in blue to show that it's a link.

Note: if you have already started writing your article before copying the link, simply open a new tab in your browser to view the file, then copy the link back into your article. If you navigate away from the article, anything you've written so far may be lost!