Is it possible to make the Discussions tab the homepage for students?
The Discussions tab is not a direct option for what can be set as the home page. Here's the Canvas guide on the options available: What layout options are available in the Course Home Page?
I can think of a couple of possible workarounds.
1.) You can copy the link of each discussions into a "Content Page" then set that content page as your front page. Left alone, this would be simple but might not be aesthetically pleasing. However, you could add some design elements and use CSS to spruce up the content page.
2.) You could use an <iframe> to embed the Discussions page of a course into a content page then set that content page as your front page. The problem with this method is then your course gets nested as you can see below.
Not without some trickery. You could use the Redirect Tool LTI app to replicate the "Home" course navigation button and then remove the actual "Home" course navigation button. Check out Ability to Rename Left Navigation Items for more information about this option. There are some good reasons not to do this though, such as the experience on mobile devices.
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