Mukund Yadav's Blog on OEM and APPS R12

Steps to find Object Fragmentation and Chained Rows in a Database is:

1) Login to OEM and Click on Targets tab and Choose Database sub tab.
2) Click on required database and follow the path under Space summary >Segment findings.
3) Click Configure tab on right side. Provide Reclaimable space(%) ,Reclaimable Space(MB), Row Chaining (%) and Click on add button and select Tablespaces to be checked for row chaining.

For Row Chaining, the navigation path is
Reports->Storage->Oracle Database Space Issues->Segments with Row Chaining Issues

For Objects Fragmentation, the navigation path is
Reports->Storage->Oracle Database Space Issues->Tablespaces with Reclaimable Space

Are you an Apps 11i DBA and want to learn R12?
Here are some of the things you can try out your self and get confidence of working on R12

* Install R12.5 (HRMS + FIN)
* Languages: US and F
* Setup Workflow mailer
* Upgrade Discoverer version
* Apply latest CPU patches
* Apply latest High Priority patches
* Upgrade to latest certified DB version
* Install XX_TOP
* Custom Standard manager for SYSADMIN requests
* Configure BPEL
* Configure Database Data guard (Optional)
* Configure R12 Monitoring through OEM
* Configure printer
* Configure iRecruitment (concept only, using virtual servers, host entries etc)
* Configure DBVault
* Configure UPK

These steps are not in sequence, so you have to apply some logic before you do it.
Also you have to search Metalink / OTN / other sites to get the details steps for one major step.
And, lastly, dont forget to take backup before any major change you making.. :-)

After doing all this, I am sure you can support R12 with confidence..