No. The user interface is very simple. Sit(x) was designed to be used by anyone. Setting up an account, creating new Sit(x) Groups, and sending federation requests are easy and only take a few minutes. There are no special skills required.
Federating Sit(x) Groups simply means joining different Sit(x) Groups so that they can share TAK data such as movement of active TAK users, sharing map markers, drawings, routes, or even photos. Federation of the groups can be done within an organization or between two or more other organizations. You can also set the duration you want the federation to last. This could span a single unique event or could be set up for long periods of time.
Yes, in fact Sit(x) can be used across various data connections. These include; Cellular data connections, WiFi, MANET/Mesh networks: i.e. Wave Relay MPU5 (for high bandwidth), and GoTenna (for low bandwidth), just to name a few.