Hello,
Those are some very basic workflow questions. I suggest you take the SAP Workflow course and/or get the workflow book:
The purpose of this forum is to help people with their workflow problems, not do their work for them.
Please let us know what YOU have done so far and what problems you are encountering.
In general you would start a workflow by using fm SAP_WAPI_CREATE_EVENT to create an event that triggers your workflow.
regards
Rick Bakker