Signed Hitchcock

Signed Hitchcock
Can anyone explain these “Writer’s Guidelines” for a magazine I am sending a story to?

I’ve written a short story and will be sending it to Alfred Hitchcock Mystery Magazine to see if they will publish it. But I am not sure what this part of their “Writer’s Guidelines” section actually means:

“Please do not justify the right-hand margin. The number of lines per page should be uniform. Indicate line breaks with a single line and a centered pound sign (#).”

I understand the part about not justifying the right margin, but what about the rest?

Any help will be appreciated.
thanks 4 the answers. I also found this awesome link that explains exactly how to type up a manuscript.

http://www.shunn.net/format/story.html

You’ve got good replies already, so all I can add is a bit of experience with AHHM. Settle in for a long wait. Some material is rejected within four to six weeks, but the wait can be more than five months.

Be aware that they’re extremely serious about no simultaneous submissions; I understand that if you withdraw something from their consideration because you’ve sold it elsewhere, you’re on their blacklist and will be rejected unread forever after.

Saboteur: Alfred Hitchcock Film Trailer (1942)