Order entity has the following distinction: since one of the attributes is the Order.customer reference attribute, you should define a view including this attribute (standard _local view does not include reference attributes).

Go to the DATA MODEL tab on the navigation panel, select the Order entity and click the New → View button. View designer page will open. Enter order-with-customer as the view name, click on customer attribute and select _minimal view for the Customer entity in the panel on the right.

Click OK in the top panel.

After that, select the Order entity and click New → Generic UI screen. Select order-with-customer in the View fields in the browser template of the GENERIC UI TEMPLATES page and click Create. Repeat the same for the editor screen template.

order-edit.xml and order-browse.xml items will appear in the Web Module on the GENERIC UI tab of the navigation panel.

You can specify localized captions for the Order screens as described above for the Customer screens.