Have a look at Bruce Dawson blog [1] - he has written many articles explaining ETW and its tooling. You may start at the summary page [2] to check the covered topics. "Ask the perf team" blog [3] contains also a lot of interesting posts on Windows diagnostics, but unfortuantely is no longer updated.
[1] https://randomascii.wordpress.com
[2] https://randomascii.wordpress.com/2015/09/24/etw-central/