To copy and paste text, use the following options:

Command What It Does
:5,8 co 12 Copy lines 5 through 8 and put after line 12
:2,4 m 8 Move lines 2 through 4 to line 8 (line 4 becomes line 8; line 3 becomes line 7; and line 2 becomes line 6)
p Put yanked or deleted line below current line
P Put yanked or deleted line above current line
Y Yank a copy of line, literally store it in a memory buffer to be put in a different place in the text later with the p or P command.
yy Yank a copy of line