To copy a file from your home directory on another host to your current directory on your local host:
rcp goya:notes part1.txt
This copies the file notes from the the user's home directory on the remote host goya to the file part1.txt in their current directory.
To copy a file from a subdirectory in your account on a remote host to a subdirectory on your local host:
rcp ubik:gnu/rcs/README tmp/gnu_README
This copies the file README from the subdirectory gnu of the user's home directory on the remote host ubik to the file gnu_README in the subdirectory tmp in their home directory on the local host.
To copy a file from a remote host on which you have an account under another username:
rcp joe@pollux:News/alt.hypertext tmp/hypertext
This user has an account on the host "pollux" with the username "joe". This copies the file alt.hypertext from the subdirectory News in joe's home directory on pollux to the file hypertext in the subdirectory tmp in their home directory on the local host.