Tramp is initially configured to use the scp program to connect to the remote host. Just type C-x C-f and then enter file name /scp:user@host:/path/to/file. For details, See Default Method, See Default User, See Default Host.
For problems related to the behavior of the remote shell, See Remote shell setup.
For changing the connection type and file access method from the defaults to one of several other options, See Connection types.
Note that some user options described in these examples are not auto loaded by Emacs. All examples require Tramp is installed and loaded:
(customize-set-variable 'tramp-verbose 6 "Enable remote command traces")