Hi @vincentakatoh,
If you want to trigger a flow when a new document is uploaded in your OneDrive for Business folder, you could consider take a try to use the "When a file is created" trigger as the trigger of your flow.
I have made a test on my side and the flow works well. My flow's configuration as below:
The flow works successfully as below when I upload a file into my OneDrive for Business folder:
The flow may spend almost 15 seconds to be fired. The flow would have its own trigger interval, there is a limit in Run duration of single flow run, the max Run duration is 30 days. More details about the limits of Run duration and retention of single flow run, please check the following article:
Run duration and retention
In addition, the trigger would have its own limits. You could consider search for corresponding connectors within the following article and check if there is a limit related to the trigger that you used:
https://docs.microsoft.com/en-us/connectors/
Best regards,
Kris