Either in an extension or as a link from another eweb page, you can redirect into the middle of a wizard by creating a link with the following format.
dynamicpage.aspx?WizardKey=4538d5d5-90e6-45d6-943e-9bd171a0b581&WizardStep=1B444A71-DF0F-4296-A0DC-FAA1EC385461&WebKey=167659f3-b172-4c55-bbf4-cf96fecabb13
Parameters:
1. WizardKey = The key of your wizard from md_wizard
2. WizardStep = The key of the form of the wizard you want to enter. The name is deceiving since it is not actually the step. Use the wzf_key from md_wizard_form.
3. WebKey = The key of your eweb page. This is the web detail key, and webcode should work as well. It comes from md_web_content as wbc_key.