Did you get the idea of how to type with GKOS on the previous page? Probably one glance at the figure was enough for you to understand the principle and to be able type a text message, still having the figure visible.
The GKOS text input compared
That figure, or simple instructions according to the same lines, could well be part of the user's handbook of a multimedia terminal. An on-screen help would also be simple and small enough.
If you think a simple text input method is easy to develop, compare GKOS for example to the instructions for using this patented method. Do you think the instructions described there could be a part of a multimedia terminal user manual?