This (your first image) is a text console... It does NOT provide access to configuration pages unless you know how to hand edit the configuration files themselves and then restart the services to reload the new settings. Pi-Star does not run an X-server (graphical) environment, and hence you can not run a web browser ON the host R-Pi.
This (second image) is the configuration page. You are set to use DStarRepeater as the main driver; it has different configuration options from MMDVMHost. However -- the D-Star Configuration appears to be the same. At the bottom of this (second) image is where the default reflector for D-Star is specified. To my knowledge, everything you have asked about is on that configuration page. Frequency is that green field.IMG_9505.JPEG
I have shown the dashboard and my other screen where I am trying to get into the settings.
What I do note is that you have not specified what radio/modem you have attached. That is six rows down from the green frequency.