Good luck
You could contact the company that makes the lawn mower to see how they can help. If they have a website; look for a contact link/button to talk to a member of staff. Ask if they can send you the part with a manual, or if you need to purchase a new lawn mower, but don't mention the latter before requesting for the part. Make sure you ask for help to put it together if you can't, you don't need a broken lawn mower as well.
I am looking to replace a lawn mower cutting disc (I think that is what it is called) for a small red Power Devil Hover Mower - Model PDG 4125 A
Its the bit that 3 plastic blades slot into.
It looks like it has >PA6< stamped on its back
I inadvertently went over a lawn spike!