>>87759666This bothered me at first too, but I figured it out.
On the menu where you choose the episode you want to watch, the thumbnails each have 4 icons under them, which can either be a sword, chest, or play button. These represent potential rewards, with the play button representing unlocking a new episode. Pay close attention to EXACTLY where the play icon is in relation to the others(for example, is it the first, second, third or forth icon shown)To make sure you get THAT reward specifically, you need to choose certain magiswords while watching that episode.
In each episode, there are always two parts where you choose a magisword, which give you two choices. In the first instance, choosing Magisword #1, the Magisword on the top, lets you get the rewards from icons 1 and 2, while Magisword #2, the Magisword on the bottom, lets you get the rewards from icons 3 or 4. Which reward you get out of those two is determined by your second choice, with the top magisword getting you the first of the two and the bottom magisword getting you the second.
Now to go into even further unnecessary detail, let's say for example the icons were:
(S) (T) (P) (S)
T=Treasure Chest
S=Sword
P=Play Button
To get the play button, and thus next episode, you would need to choose the bottom magisword during the first choice, and the top magisword during the next one. So essentially:
Choice 1+Choice 1=Reward 1(S)
Choice 1+Choice 2=Reward 2(T)
Choice 2+Choice 1=Reward 3(P)
Choice 2+Choice 2=Reward 4(S)
As an example, I know that to get the episode reward for the first video, when watching you need to choose Choice 2(Snowball Magisword) and Choice 1(Blowdryer Magisword).
If, even after all this explaining, you still don't understand, I could just make you a cheat sheet of what swords to choose in each episode 
