@Jack_Ketch89
I still do not know what “Preview” you are talking about.
Try to add a 2nd definition column.
There is only one column definition in your course!!!
I do not create courses myself, but there must be probably an error how you try to use Memrise as a course owner.
When I hit the “Learn” button myself, I too run into the “Whoops. Could not load the session. Sorry.” error message.
Interestingly, there is no red error message in the browser console.
So it is an internal server error.
IMHO you can not use Memrise the web portal (nor the mobile apps) very well without a ton’s of installed user scripts.
I described it here: Can any teachers with groups help me please? Words learnt/in long term memory are better than points gained?
You do not need necessarily have to have an IT degree, but you need to be willed to jump into the deep water how to install / use them.
Same stuff as on DuoLingo…
For example you have to search the forum what scripts you can find and how to run them with browser addons.
Try AnkiSRS.
But you definitely need to be a person with a (more) deep technical background to understand and use it.
Even me, a Java developer with years of IT experience, has to invest DAYS to read into the Anki manual, Windows application settings and search for interesting forum threads and blogs, how best to use this program.
It will probably take me weeks or months to get any gist how I can import and review my Memrise courses very well by tuning standard settings.
Anki has out-of-the-box support for overdueness - a feature which was killed by Memrise staff a few months ago with a code update making Cooljingle’s great user script unsupportable).
Memrise is A LOT easier than Anki and I have been using Memrise for 1,2 years.
Then you better use Open source tools…like AnkiSRS & Co.
I get not too many Memrise Pro upgrade screens, but YES, they will be shown from time to time when I reach new streaks on courses (even completed ones).
Or I get offers per e-mail as I have not turned it off.
So prepared…but I think you could live with that.
It is not that annoying like how DuoLingo does it in their Android app after each lesson.
Was that announced in the newspaper that Memrise has no bugs as well as? 
The last code update was last week Wednesday.
With every code update the past months they either killed old features, updated their API (user scripts not working anymore), introduced new bugs or made the main dashboard (completely) unuseable; it still is a bit.
After the update I can not type anymore in my courses.
And now as this basic functionality was recovered by Cooljingle with his “all typing” script update, the
onscreen keyboard for diacretics is gone (so Memrise made another change)…fantastico!
.
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You just need to scroll past the news in the announcement sub-forums and “endlss” user feedbacks (bug reports or complains) to get a clue what is going on with the Memrise web portal.
IMHO they seem to not have any testing departement or QS quality management, just like DuoLingo.
You, as the end user, are their BETA tester!
So, if you want to use Memrise, you better be prepared for this stuff!
And without any user script you can NOT even turn OFF this timer on the web site!!!
I “learned” about >~5000 Portuguese “words” (incl. phrases/sentences) on Memrise in 15 months…so if you are patient, and have a low frustration level, you might learn to live with it.
The updates and bugs get more often…
I just can hope that this update stuff ends at some time once the website is useable again.
Depending on the language (e.g Asia) you might miss important features (turn off hint keyboard, show keyboard clearfix, problems with new “Auto accept”, etc.)
My best suggestion: Try it for yourself…be patient…test around.
We will try to help you as best as we can if you run into any questions.
I invite you rather to use the massive upload. Basically you type in a spreadsheet like .xls one column your old english , the other the modern one. then a global copy.