The following instructions include variations for linking to a pre-uploaded binary document file (generally the wiser approach), and for uploading the binary file while building the link:
Login and navigate to the page on which the link is to appear; select "Work on this Page" or "Work on this Page (All Changes)."
Find a "Click to insert new element" at an appropriate location for the the link; if there is no such item, then use one of the approaches discussed in step 6 of Copying and Pasting an Element.
Click on "Click to insert new element".
In the Element Gallery, click on "Link & List Elements" to expand that portion of the list.
Select the type of link you want to create. To create a simple link, click on "Link"; in class, choose "Link."
Click on "Click here to define the Link element".
Fill in the "link header" with the text that you want to be the visible, clickable link, and then click on the "next" button.
See the commentary after step 14, below
You will see the dialog for constructing the link, with the Link Action tab active:
When building a link to a file that has already been uploaded into CommonSpot (either according to the method described elsewhere, or while building a prior link), select a Type of "Uploaded document" and then click on "Choose from current subsite" or "Choose" (which together replace the old Page Gallery); click on the "Next" button; go to step 12.
When building a link to a file that hasn't yet been, but should now be, uploaded into CommonSpot, select a Type of "New Uploaded File"; click on the "Next" button; go to step 9.
When building a link to a file that is already online, but not in CommonSpot, select a Type of "Unregistered URL or Relative Internal URL" (the last choice on that pop-up). Fill in the URL for the file; be sure to give the entire URL, starting with "http://"; click on the "Next" button; go to step 14.
The document needs to be uploaded, so click on the "Browse" button and select your document file; click on the "Open" button to select the file.
Once selected, choose the category (typically "Other Document"), give it a title, and click on the orange down-arrow to pre-fill the other fields. The title should be descriptive and unique within CommonSpot.
Click on the "Next" button to complete the upload and link-building process. Go to step 14.
If you are linking to a document that is already in CommonSpot, click on either "Choose from current subsite..." or "Choose..."; in the list of documents (which will not include CommonSpot pages), click to highlight the one you want, and then click on "Use Highlighted Page."
Observe the title and URL at the bottom of the Insert Link lightbox, and click on "Save."
When ready, click on the yellow work-in-progress icon to publish the change; in class, wait your turn to click on the "OK" button.
It is both kind and wise to include, in or adjacent to the clickable link text, some indication of the type and size of the file (e.g., "250 KB PDF file"). Mentioning the size is important because of the wide variations in connection speed within your audience. Do not say anything about what will happen when the link is followed, because different browsers exhibit different behavior (e.g., opening in the browser window, opening in a separate application, offering to save to disk, etc.), depending on the browser's abilities and on the user's choices for configuring that browser. For example, people using Internet Explorer on Windows may well find that a Word document opens within the browser window. Others may find that it downloads the file and then launches Word to open the document. Still others will have to select whether to save or open the file. These variations are likely to be consistent for any one user (depending on their software versions and configuration settings), so they should not be taken by surprise if you have revealed the file type, but it is impossible for you to predict what will happen for all your users, so be careful to choose a wording that will apply to any of these variations (e.g., identify the link by file type and size, but don't say, "to open").