you just have to drag the widget “immonex: Energy Scale” to of the property detail page sidebars (via Appearance > Widgets). Alternatively, you can add it by using the shortcode [immonex-energy-scale] at the desired location (see the plugin documentation for all available options/parameters).
If the energy scale is not displayed, in most cases the required data are missing. Which kind of data source have you selected in the plugin configuration (Settings > Energy Efficiency Scale > Data Source)?
Could you please answer in English? My Spanish is not so good… 😉
Basically, if you select “Energy Efficiency Meta Box in Property Form” as data source in the plugin configuration (Settings > Energy Efficiency Scale > Tab “Data Source”), the property edit form (Listings) is extended by a box with the title “Energy Efficiency (immonex Energy Scale Pro)”. All required values for generating the energy scale can be entered here.
Alternatively, if you use an own set of individual custom fields that contain the energy values, select “manual Custom Field Mapping” as data source and enter the respective field names (not values!) in the form section below.