Install the package, or AUR for the latest revision. Note that truecolor support is only available in the latter.
Mosh sessions by default use a random UDP port between 60000 to 61000, so this port range in the server should be accessible.
To connect, run:
$ mosh user@server-address
To send ssh options for connecting:
$ mosh --ssh="ssh -p 2222" user@server-address
You can make options permanent by using the usual OpenSSH Client Configuration.
--predict=experimentalwhich produces more aggressive echoing of local keystrokes. Users interested in low-latency visual confirmation of keyboard input may prefer this prediction mode.