How do I use visual mode commands in extend mode?

[qwbarch]

If I wanted to select the words from line 15-30, here's what I would do:

:15
30gg

I wanted to try creating cursors from lines 15-30, but this failed:

c-n
30gg

This simply jumps to line 30 without creating any additional cursors.
How can I achieve what I'm looking for?

[mg979]

<c-n>

Then either m operator

15mj

or :VMSearch

15:VMSearch

or from visual mode

:h vm-visual-mode

If you wanted to create a column of cursors, you would just do

15<c-down>