Booking for voluntary for Covid19 testing can be done through this link https://guichet.public.lu/en/citoyens/sante-social/coronavirus/depistage-covid-19.html
Why should someone check?
Government of Luxembourg quotes the following on why you should do so: A majority of those infected show little or no symptoms or are already contagious before showing symptoms. Hence, it may be that one carries the virus (and is therefore contagious) without knowing it.
How can you do it?
You need an invitation code for testing. The code arrives by post. Every week, new invites are posted. Without the invitation code, it is not possible to book an appointment.
With an invitation code, can people test anytime?
People can test within the available appointments. It is recommended to take an appointment as soon as you received the invitation code.