You can't have multiple commands in a single line unless you use a : to separate them.
For example, instead of...
COLOR 7 LOCATE 14,14,-100 INPUT "SMTH",EP
...you should write...
COLOR 7:LOCATE 14,14,-100:INPUT "SMTH",EP
Also, your INPUT command needs another parameter, which is the variable to store the user's input. It goes after the guiding text string.
Instead of just guiding text...
INPUT "Pick an episode: "
...include a variable to store what the user picked...
INPUT "Pick an episode: ",EP
Also, it's syntax*, not 'sitnx'.
Sorry. terrible speller. i'm trying to make a game where you watch a made up tv series i made myself called "Smile Quest". it has only a few episodes. but more episodes will be added on further updates. can you rate my idea? 0-100 stars?