if you are using a USB to serial adapter you will need to install a driver.  If the driver is not installed or recognized you will not see additional options for connecting your telescope under "Configure".  If you have installed the driver but do not see further connection options consider the following:

1.  Restart you computer - often required for drivers to be recognized after installation.

2.  Reinstall the driver - perhaps it was not successfully installed the first time.

3.  Contact the support department of the USB to serial manufacturer and confirm that the driver you are installing is both the most current driver and compatible with your operating system (this is an important consideration for Mac users running OS X Sierra).