How to use this latching relay to simulate button press?
Probably you want do do something like this:-



simulate this circuit &ndash; Schematic created using CircuitLab
The pin diagram is clearly shown on the datasheet:

Note that (for historical reasons) the pin diagram shows the BOTTOM view, rather than top view as most modern datasheets show.
Coils are between 10(+) &amp; 6(-) for SET and 1(+) and 5(-) for RESET.
In the SET state, pins 3 &amp; 4 are connected, and pins 8 &amp; 7 are connected.
In the RESET state, pins 2 &amp; 3 are connected, and pins 8  &amp; 9 are connected.
You just pulse one coil or the other briefly to change the state, and it persists until the next pulse even if the power is removed. So if you pulse it to actuate the simulated button and the power goes off before it is released, the simulated button will remain held indefinitely.

If the goal is a simple momentary (not sustained) contact, a latching relay may be a poor choice as it requires twice the drive circuitry of a normal relay and may complicate safety or other operational factors due to it remembering the state.