I would create a new calculated field summing all bronze + gold + silver medals. I would use Rank table calculation and filter the rank to show top 10 only.
It would help if you could attach tbwx file?
You can use the steps to create a field for ranking in this thread
Then just apply the RANK() function to the field you wish the rank to be based on.
Example below in Superstore, ranking on sales... you could substitute sales for number of medals...