Help please! Excluding pages

Hi,

I have downloaded your plugin and I am trying to exclude a few posts from the search…I have tried adding in the post ID number (postid-1631) in a number of different ways but it keeps saying:

Oops, there are errors in your submit:
incorrect format for field Exclude some post or page IDs
Please go back and check your settings again.

Can you kindly advise?
Many thanks.
Michelle

https://wordpress.org/plugins/search-everything/