How to create a 'Next button' to show o/p of each file one by one

filepath='C:\Users\Parag\Desktop\12-08-15';

FileName={};

dirListing = dir([filepath '/*.txt*']);

for Index = 1:length(dirListing)

 baseFileName = dirListing(Index).name;

 FileName=[FileName,baseFileName]

end

 file =importdata(FileName);

Fr=file(:,1);

   Hr=file(:,2);

   Ar=file(:,3);

   Fr=Fr./1000000;
.........................

[Jan]

Start with replacing the failing concatenation of file names by:

dirListing = dir(fullfile(filepath,  '*.txt*'));
FileName   = fullfil(filepath, {dirListing.name});

Then explain where the "Next" button should appear and what "show o/p of each file one by one" exactly means.