The proper documentation is TI data sheet D2780, October 1983.
Connection is straightforward.
The sonar sensor attaches to J2 and J3. Keep those leads short. So put a big electrolytic across the power inputs, and isolate the thing from other loads. When an echo is detected, ECHO will go high. INIT and ECHO can be connected directly to timer channels of the 68HC11 without harm, but the power supplies should be isolated.