Im having an issue with the review raw file option

I'm new to brainstorm. I have a .mat file that I want to review but everytime I try this error message appears.
image

I have altered the .mat file so the Data and Time are in a matrix and not all in 1 cell.
I would appricate any help in trying to solve this.
Thank you

If you are new to Brainstorm, I'd recommend you start by following the introduction tutorials, at least until #19, and using the example dataset provided.

Apparently your .mat file was not created with FieldTrip.
If it only contains a variable with a matrix of data (channels x time or time x channels), use the file format "EEG: Matlab matrix" instead.

How would I use the 'EEG:Matlab Matrix' file format. thank you for replying

Just select it in the file format selection in the dialog window to select the file.

Can you please confirm that you have followed the introduction tutorials, at least until #19, and the EEG/Epilepsy tutorial?