A new user of MuseScore, his difficulties

On January 14, 2022 I began using musescore 3.4.2-bp153.1.101-x86_64, revision 148e43f, in a 64-bit, Leap-15.3, Linux operating system in Oracle VM (Virtual Machine) VirtualBox 6.1.30 r 148432 (Qt 5.6.2), which in turn was installed in a 64-bit Windows 10 Home Edition operating system on my Dell notebook computer. I installed the software package musescore from an openSUSE, Leap-15.3 online software repository. Along with it I also had installed the software packages

musescore-fonts 3.4.2-bp153.1.101-x86_64,
fluid-soundfont-gm 3.1-bp153.1.14-noarch,
fluid-soundfont-gs 3.1-bp153.1.14-noarch,
timidity 2.14.0-bp153.1.20-x86_64, and
libpoartmidi0 217-bp153.1.31-x86_64.

My overall goal is to produce a score for a largely piano or electric-piano composition on a Recordable Compact Disc (CD-R) I purchased which would be detailed enough that I could play much of that composition on an electric piano myself and have that playing sound close to the recorded piano playing. With MuseScore I was gratefully successful in putting three notes above each other in a treble clef and two other notes above each other in a bass clef, so, with vertical alignment among those five notes, the writing of a five-note piano chord. This was the feature I wanted to have in writing piano chords! I request help with the following difficulties using MuseScore.

1) At least half solved: In setting up my first score using MuseScore I entered the name of the composer of a composition on the purchased CD-R followed by a question mark. Later, after viewing data for that CD-R, I could in principle remove that question mark and add a year of copyright on the MuseScore, File, Score Properties… page. But after making those respective changes on that page and clicking on “OK,” those changes did not appear near the top of the score for that composition! Saving that file and restarting MuseScore did not enable those revised data to appear near the top of that score, despite the fact that the “Score Properties…” page then had the correct, revised data on it. However, at the top of the score I could right-touchpad-click and select “Edit Element,” and then remove the question mark after the composer’s name. Unfortunately I could not do a similar thing to enable the year of copyright to appear in that window at the top of the score, perhaps because I did not enter a year of copyright in the first place for that composition.

2a) How may I properly select just one note or one rest in a score?
2b) Then afterward how may I delete that note or rest?
2c) Suppose I would want to select a group of notes and/or rests, but not a whole clef of notes and rests, and then delete them. How would I do that?

In your answers to these questions please include plenty of detail, such as clicking on a left- or right-touchpad or “mouse” button and clicking on an icon with the symbol of a musical note and a capital N in it.

3) How may I add a half-measure rest in 4/4 time using MuseScore? I think that would be a black rectangle resting on a staff line. I would like my first measure in 4/4 time in this score to include four beats in it. But currently it only has two beats in it. Eventually I was able to see a blue-colored, half-rest symbol moving over my computer screen. But I could not get it to appear in the end of the measure in which I wanted it to appear. Instead I have had one or more additional, unintended quarter rests appearing in the second measure of the score.

4) My first measure in 4/4 time in this composition has a chord of vertically aligned quarter notes followed by a quarter rest, so making my total of two beats. Each quarter rest in the treble and bass clefs has a short, grey-colored line segment above it. Perhaps those segments are there to get my attention that that measure in 4/4 has only two beats, instead of four beats in it; or else those short line segments might indicate trouble with further trouble in my trying to input a trailing half rest in that measure.

I’d like to be able to quickly select and erase musical symbols in MuseScore, as well as to be able to add the musical symbols I want to add to a score. Clicking on “Edit, Undo” often worked for me to delete symbols input by me in MuseScore. But I would like to do better than that. I think my above-mentioned troubles 2-5 with MuseScore are likely due to my errors of my part.

5) A friend of mine mentioned an, I suppose, imaginary computer code which would allow, in effect, a score to automatically be produced while a song is being played. But perhaps such a computer code may not exist, even for a single musical instrument being played. Do you agree with such nonexistence?

I thank whoever made the considerable effort in trying to guide a new user of MuseScore with helpful comments! From the Internet I downloaded a 264-page handbook for MuseScore which is dated “Jun 14 2021,” which probably means June 14, 2021.