How to add a full bar's reat in the second voice

Here is a snippet of notation to be entered:

In regular note entry I could not find a way to get that 'untouched bar' full bar rest entered, closest was a dotted whole rest - not what's on the handout.

Fortunately, the tenor and empty bass lines above came to the rescue. As I had already transcribed the four voices into SATB format I could select these two tenor and bass bars and Tools | Implode them. Nothing really appeared to happen, the tenor bar appeared to be unchanged. I had nothing to lose, hunting a little further I found 'Voices' and, more importantly Tools | Voices | Exchange voices 1-2; still nothing promising appeared to happen. Exchange voices 1-2 again, however seemed to do the trick of getting the full bar rest appearing. Copy this two-voice bar back to the bass line of the accompaniment and switch voices 1-2 again: Ta Dah!

Just to clean up, apply a beam and do the explode up on the tenor line and Bob's your mother's brother - see bar 51. BREAK FORTH INTO JOY - Caleb Simper.mscz

Now, I know for some of you more accomplished MuseScorers this may be an old trick but it took me quite a while to figure it out, these 'untouched' bar rests are an odd beast, so I hope this work-around may help some people to preserve some sparse hair.

On a slightly different note: What does the bracketed Piano (p) actually mean?