In order to refresh your report, you can click on the refresh icon in the action bar of your report and then you are facing two options. Either refresh your report or clear all cache and then refresh your report.
Use this option to regenerate all queries and re run them again. This is useful if your report hasn't been refreshed for a long time (more than a few minutes) and will help you refresh all your charts. You can see when your report was loaded for the last time next to the refresh icon.
Clear cache & refresh
This is useful if you have used the refresh button but you feel like that the figures you are seeing are not up to date. When clicking on this button we will get rid of all values stored in cache and run the query against your warehouse. Be aware that this option will increase cost on your warehouse side.
If you want to be familiar with how caching works at Whaly please read: