New to brave have been using for a few days but not getting any rewards yet
Have you checked if ad notifications are enabled in the notification options?
Try forcing the closing of the browser, clearing the cache or deleting all the browser data (only if you have not received any reward and have all the important data saved or synchronized)
Also depending on the country in which you are you will receive more or less ads or none.
The browser collect information based on what you are looking for on the internet. Cars, clothes, cryptocurrencies, etc.
Here you can find a list of countries where a certain amount of ads are available.