Ikasu mp4 touchscreen

Question

I am trying to put videos on my MP4 and have downloaded a file converter onto my computer, whihc works. However, I am not sure what format the files should be in lorder to work on my mp4. I have tried AVI, MPEG and WMA files and they won't work due to a 'file error'. Please help I have already spent 2 days trying to sort this out. Thank you