Copying text in screen is tedious

[Pablo]

For Copying the text in screen, after pressing Ctrl-A, Ctrl-[, why is the
cursor always stuck at the bottom right and we have to move it 25 columns
above and then 80 coloumns left and then press Enter to start copying?
Can't the cursor just always start from the top left instead of the bottom
right?

And if there is more than one page of text, in copy mode, why does one
get a blank screen pressing Page-up or Page-down keys? How to copy text
more than one page at a time?

Thanks,
Pablo