Notes of Differing Durations on Same Beat?

In the example attached, I would like the lowest F2 whole note to extend and sustain through 8 beats (two bars). This would require two whole notes tied together.

I can't seem to figure out how to add a whole note to the second bar without it erasing all of the other notes I've already written. If I try to write the notes in order (progressively, one chord/note at a time), I can't seem to figure out how to get MuseScore to allow for a whole note and a quarter note to be in the same vertical space. This is extremely basic notation, so I'm assuming this is user error and not a limitation of the program - can someone please help me understand how to properly enter notes of differing durations on the same beat?

Thanks!