What should I do if I lost my MacBook/ it is stolen , and I’ve not set up find my on the device?
How can I find my MacBook Air if it is stolen/lost and I don’t have Find My Device set on it?
MacBook Air 13″, macOS 11.2
Read what to do...
'If your Mac is lost or stolen.' Click here --> https://support.apple.com/HT204756
If you did not set up Find My in advance it is too late to do that now. You'll have to resort to conventional methods to try to locate it such as asking places you have visited if they have seen it, etc.