.midas is a file format that only Skyline understands. When you use Skyline to extract chromatograms from a .wiff file, Skyline will create a .midas file if Skyline finds any MIDAS spectra in the .wiff file.
It might be easier for us to help you if we could see the files that you already have.
In Skyline you can use the menu item:
File > Share
to create a .zip file containing your Skyline document and supporting files including extracted chromatograms, spectral libraries, and that .midas file if it got created.
It would also be helpful if you sent us at least one of your .wiff files and the .wiff.scan file that goes along with it.
You can upload all of those files here: