Multiple video's in a matrix with timecode

Hi,

For an assignment I'm trying to load in 2 txt files (one with only timecodes and one with text). I've got 26 video's, for every letter in the alphabet one. Now I want it to do is: read the timecode. When it is that time, get the next line from the other txt file. Then it needs to split the line in seperated characters and grab the matching character-video and put it in a matrix. So when this happens, you should just see one specific line in video's (in a matrix).

Now I've got this all done, but I only get to see a white screen.
So my question is how to get the video's been shown correctly in the matrix?

Thanks