Converting (unknown/ascii) file to .eeg or .eds file type for FieldTrip Toolbox

Hi, I'm trying to do preprocessing on EEG data that was already cut into the bits I'm interested in using FieldTrip for baseline analysis.

I have the header information stored in a .mat file, but ft_read_header does not accept matlab files. I received the 'original' header file from my colleagues but it's odd, it's a text file without extension, the file type just says 'file'. Using open(filename) just gives me an empty file, if I double click I see a line with the electrode names.

It was suggested I convert the file into an .eeg or .eds file but I don't know how, without knowing the current type. Alternatively I thought I might adjust the .mat file in such a way that FieldTrip accepts it, or would that cause any issues?

Thanks for suggestions! Pia