I would suggest first looking at the logs themselves. I would search for the log-in logs and check if the contain the desired information.
If it contains the relevant information (I think source country is the most relevant field) I suggest creating a statistical table widget and add the "Source Country" (make sure the checkbox for show each value in a different row) and log.
This will create a widget that counts how many logs you have from each source country and will show you the top X (which can be changed in the widget itself). This will show all logs though, so the next step is to create a filter that will narrow it for relevant logs only, such as relevant blades, action equals Log In etc.
After creating a widget you can perform a drill down by double clicking the row in the widget and see the actual logs. By the result you'll see if you used the filter correctly - make sure you didn't filter out relevant logs and that irrelevant logs are filtered out.
This in general is suggested for every widget you create - go from the logs that are of interest, see which fields are important to you and which filters you can use to filter other traffic that might have info on relevant fields. You can always check integrity of the widget by drilling down.
Kind regards, Amir Senn