So after fighting with SF Audio Studio 17 for over two hours to export as a MP3, I learned a few things that will help you.
1st is that Audio Studio is the most worthless program ever. The developers clearly put a lot of work into the program and created a lot of cool features yet missed the most important element of any production software. That is the ability to export your work in a common usable format. After spending hours editing a podcast episode then another 2 hours trying to export it to a MP3, I learned that Audio Studio 17 and previous editions, lack to the ability to export any project with more than two channels to MP3 format. This is absurd, especially for a dedicated audio production software. I produce multiple podcasts and have found that Movie Edit Pro does a better job of creating podcasts than AS17. Not only is it easier to use, but it a wide array of audio tools, can handle several audio tracks, and actually export your podcast or other audio project to MP3, without any issues. Which is sad that Magix's video software does better audio than their own audio software. As a result, I have found Audio Studio to be completely worthless.
So regarding the "There is no template available for this format" issue that many people have and that Magix has not fixed, here is the solution.
1. Make sure you are only using the first two channels
2. Click on "view" at the top of the screen.
3. Go to "File Properties"
4. Click on "11. Audio Channels" and select "2".
At this point you can export to mp3. However, channels 1 and 2 are in stereo so left and right are different. This can be fixed when exporting by selecting Mono under the Custom options on the Save As screen.
Hopefully this MP3 issue AS17 will get fixed. I really like the program, but not being able to export to MP3 just makes it worthless and just causes me to keep using their video software to do my audio projects.