There should be one single When step per scenario. If you feel compelled to add more, it is usually a sign that you should split the scenario up in multiple scenarios or that some When steps could be converted into Given steps.

Noncompliant Code Example

Scenario: Add a nice bike to my cart
  Given I am a customer
  When I go to the nice bike product page
  And I add the nice bike to my cart           # Noncompliant
  Then I should see the nice bike in my cart

Compliant Solution

Scenario: Add a nice bike to my cart
  Given I am a customer
  And I am on the nice bike product page
  When I add the nice bike to my cart
  Then I should see the nice bike in my cart