The process you use to support members on work time depends on the situation, and the Union Leave provisions in your collective agreement. If a member asks for union representation for a meeting with the employer, then you take Union Leave with pay to attend the meeting as a Shop Steward. 

If the member is asking a question and more research and discussion is needed, Shop Stewards are expected to do this on non-work time.

If the member has a complaint of an urgent nature, you can usually take Union Leave with pay to investigate this possible grievance.

Each Collective Agreement is a bit different so make sure to look in yours in the section usually called Union Leave or Representation for details.

Still not sure? Ask your Chief Shop Steward or Local Executive member.