Display the course with checkbox on the page in design of the theme,
read the data from webservice over API.
When cklick on button 'Anmeldung' (register) slide out a form,
when ckick on button 'Abschicken' (send) then
- check the input fields,
- an email will be sent to the subscribers and company (BCC)
- for each course an entry in the database over API
In the settings is the URL of the API and the company email deposited.