Open the membership form of the site: the sign in form, the sign up form or the account of the signed-in member. The step presses the button the theme offers for it (data-portal), or asks for the form by its address when the theme has none.
Examples
When I open the membership sign in form
When I open the membership sign up form
When I open the membership account form
When we open the membership sign in form
And I open the membership sign up form
Pattern
When(/^(?:I |we )?open the membership (sign in|sign up|account) form$/, …)
Part of @webship-js/ghost-steps (github.com/webship/ghost-steps), a step pack for Webship-js 2.0.x.