Move and merge pitch range of notes from bass stave to treble stave and vice versa

First to say, not a native English speaking so apologize.

Please have a look on my attachment of the issue. I'd have my composition that was imported from a midi file played by me. Importing process went smoothly until I noticed that notes are put on the stave, to say, madly. Too high notes are put on the bass stave.

I have gone through MuseScore instructions and forum as much as I could, until I was forced to create my account and this topic. I found almost similar conversations from an earlier time, but unfortunately I either didn’t understand or they just didn’t help with this.

So I'd need to move the too high pitch notes from the bass to treble stave, without deleting those already there. On few occasions, MuseScore automagically replaced the treble cleff with bass clef, when the melody is a way lower. On some other occasions too, the note pitch placement are pleasing. But, to say, most of the piece is really bad concerning the too high notes on the bass stave. According to my knowledge of playable sheet music, notes played by left hand must be on the bass stave, and notes played by right hand must be on the treble stave, speaking of piano notes, or organ notes.