How can I create customized subject area ?
I need to do my analysis using OBIEE (12c) based on more than one table ??
You can either go through the tutorials to learn about how to model things in the RDP or follow an official training.
There isn't a 1-sentence reply to your question other than: get your physical sources in the RPD, model a business model and create a subject area on top of it.
Please lead me which tutorials should I look for??
Is there specific tool in oracle should I used to create my own subject area??
It sounds like you start from the very beginning. Don't expect something quick or just taking 3 clicks.
https://apexapps.oracle.com/pls/apex/f?p=44785:24:0:::24:P24_CONTENT_ID,P24_PREV_PAGE:12166,1
If you want to just connect 2 tables and build a chart on top of it, maybe you want to look at Data Visualization, even if the one in 12c is a bit limited it will be faster and simpler than going through the RPD development with the Administration tool.
