Press a button of the toolbar at the top right of a back-office page, by its label: "Add new category", "Add new customer", "Add new cart rule", "Edit category"… They are links with an icon, which the generic press step (buttons only) does not find. ("Add new product" opens a dialog: use the step that creates a product.)
Examples
When I press the back office toolbar button "Add new category"
When I press the back office toolbar button "Add new cart rule"
When we press the back office toolbar button "Add new customer"
And I press the back office toolbar button "Add new address"
When I press the back office toolbar button "Edit category"
Pattern
When(/^(I |we )*press the back office toolbar button "([^"]*)"$/, …)
Part of @webship-js/prestashop-steps (github.com/webship/prestashop-steps), a step pack for Webship-js 2.0.x.