"How do I pass the results obtained from one function to the next function. for example, how do I get my imported data to plot without repeating the whole code? "
There are several ways to do this. Assuming the import function is defined within your appdesigner file, the cleanest method would be to merely pass the data into the plotting function as an additional input. Alternatively, you could store the data in the "UserData" property of the axis handle and then retreive it from within your plotting function.
app.UIAxes.UserData = myData; %store the data
myData = app.UIAxes.UserData; %retrieve the data from within the plotting function
Secondly, how can I display my already imported data in form of a table in AppDesigner as it is
Here's instructions how to set up the table when the app first starts
And here are some demos showing how to update the table once there is new data
