@guru89044, sorry I missed this question, you should check out following blog for overlaying time series...
https://www.splunk.com/blog/2012/02/19/compare-two-time-ranges-in-one-report.html
You would want to use multisearch command or appendcol command instead of append.
You should also check out timewrap command available from Splunk 6.5 and above.
For learning Splunk you can check out Splunk Fundamentals course and some of other free elearning courses on Splunk Education. Splunk Docs and Splunk Dev are good documentation and tutorial sites. You can also check out Splunk How To channel on Youtube and Splunk Blogs.
... View more