First thing, dont use telnet, since its not secure (passwords are sent in plain text)
Instead of telnet, use ssh or sftp etc (they are encrypted)
should be explanatory but lets say i had an account 'foo' on machine at ip 123.456.78.910 that i wanted to connect to
Code:
ssh -l foo 123.456.78.910
would get you on there...
but to just transfer a file, use sftp or something