I need to make the following changes urgently on my dns server

from
coulsdon.ac.uk MX 1 email.coulsdon.ac.uk

to
coulsdon.ac.uk MX 30 slr.jms.ja.net.
coulsdon.ac.uk MX 20 jms.ja.net.
coulsdon.ac.uk MX 1 email.coulsdon.ac.uk.

but i cant seee how to put in the external host address - can anyone help

Michele