Get data (tree structure) from a Excel file into GUI

Hi Guys,

Before I explain my situation I would first like to address that I only have average Matlab skills and no skills concerning GUI's.

The thing I want to do is to get data that I recorded using the Xsens Mocap system into my own made GUI. The data that I got out is orientation data of body segments (in quaternions). I already made a script to get all the data out of the .MVNX file (the file format that the software of Xsens uses to export data which can be opened in Excel or Matlab), which works fine. Now I want to implement this script into my GUI. What I eventually would like to have is the possibility to select a file in the GUI (already made that), and then select what kind of data you would like to show in the figure using a popup menu.

The problem is that I have no idea where to put my script inside the GUI... The way I have set it up now doesn't cause any errors, but I don't see my data viewed in the workspace either (don't know if I should see that when running a GUI?). An example of data that I would like to show is for example the first column of the 'NewOrientation' data.

I have added the script that I currently have for the GUI as attachment. Any help will be appreciated!!