To allow remote control, your partner should also have a TeamViewer and you need to tell your partner the ID and password of your teamviewer, found in the Allow Remote Control pane. This will allow them to connect to your computer and control it.
To control or transfer files to a remote computer, you should enter your partner's ID in the Control Remote Computer pane.Then select whether Remote control or File transfer and click Connect to partner. This will require a password that you should also get to your partner.