[Can you remove the “Solution” marker from your post above? That’s fighting with me when I try to post.]
“Card 1 : front+back”
I saw that! That is actually the “card type” (notes and cards are different). I was trying to figure out if this is a busted version of another template that we want to salvage, but Default templates are always replaceable, so let’s not worry about that.
On the front template:
Remove {{type:Verso}}
On the back template:
Below what is there now, add
<hr id=answer>
{{Verso}}
On styling:
Remove the line that says background-color: #F3ECAE;
[Unless you are using the “resize image add-on”, you can also remove everything from /*Start through add-on*/, if you like.]
Outside of this window
Manage Note Types > select this one > Rename > Change the name to “Basic-edited” or something else useful to you.
I think that should do it, but if you still have issues, show them to me and we’ll see what else we can tweak.