To manually start a connection using the connection panel:
Click on a protocol (FTP, SFTP, S3, or WebDAV) at the top of the connection panel.
Fill out the form that appears with the information required to connect to your server. If you don't know this information, ask the person who administrates the server you want to connect to.
Click Connect to connect to the server within Transmit, or click Mount as Disk to mount the server as a disk in the Finder. See also: Using Transmit Disk