amending entered notes

Hi,

When I enter notes on a new piece of music, and I inadvertently put the wrong note in a bar, how do I

a) move it - if it is not the note I intended - up or down
b) alter it - if it is the wrong type of note - too long or too short
c) delete it - does this effect the notes surrounding it is the music ?

So far, I have not found out how to do these simple things

a) Alt-up/down
b) retype the note value, using the top row numbers, or by clicking in the left panel, or by using Shift-Alt-Left/Right to shorten extend by the grid value
c) by typing the delete or backspace key. This won’t affect following notes unless Insert mode is on.

https://www.dropbox.com/s/rhq2udlfq985m7b/A%20Beginner's%20Guide%20to%20Dorico.pdf?dl=0