Splunk is licensed based on the maximum amount of data you index per day and the best way to understand your license usage is to look at the licensing page. The free version allows up to 500MB per day (you can go over this limit a certain amount of times in a 30 day window), you can buy licenses in various increments (1GB, 2GB, 5GB, 10GB, 15GB and 20GB) to suit the amount of data you index on a daily basis. The newest trial version of Splunk Light gives you 5GB for 30 days to help you better understand what volume you should expect.
To answer your question about number of files, it looks like from your first screen shot you have 983 files being indexed from /ServerLogs. Those files are grouped into 5 sources and 4 source types. Select Host (1) and click on the link. Splunk Light should then list all of the log events collected from your system and verify that all your data is being collected.
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