Traffic controllers & instructions
Look at the instruction and whom it applies to.

Follow instructions from authorised, recognisable traffic controllers and police. These take precedence over lights, signs and ordinary rules. A green light does not permit ignoring a stop instruction.
An arm raised vertically is the general stop signal. Directional stop signals depend on your approach: from the front, rear or indicated side. Stop in a controlled way and wait for a further instruction.
Two horizontally outstretched arms signal a stop for traffic approaching the controller from both the front and rear. This is not a general stop for all directions. Study the simplified diagrams; consult RVV Annex II for the full official set.