change time signature and convert quarter notes to eights

I imported a midi file , and MuseScore made a score that is a good starting place, considering that the midi file was computer generated from a .wav file with Linux “WaoN” utility, and has some problems that I can fix manually.

I changed the time signature to 4/4, and that worked, but the music that should be in one bar is stretched over two bars, and it is not right for this piece.

Is there a way to coerce this to alter the notes, every not halved?

Rob

Phyllis Chang (playing tenor and bass recorder duet ) "This is a song very popular in 70’s till now among Chinese in different regional. English translation: The moon represents my heart."
https://www.youtube.com/watch?v=wV6ebgIQvbQ
*** my work in progress attached ***