As the oracle user backup the repo
emctl exportconfig oms
To install BI
cd /oracle/middleware/oms/bin
./configureBIP

Enter the password

Example output

Creating SYSMAN_BIPPLATFORM Schema in EM Repository Database
 
Configuring BI Publisher in Oracle Home located in /oracle/middleware/Oracle_BI1 ... 
Processing command line ....
Repository Creation Utility - Checking Prerequisites
Checking Global Prerequisites
Repository Creation Utility - Checking Prerequisites
Checking Component Prerequisites
Repository Creation Utility - Creating Tablespaces

[…]

Configuring BI Publisher in Oracle Home located in /oracle/work/middleware/Oracle_BI1 ... 
Extending domain with BI Publisher. This operations can take some time. Do not interrupt this command while it is running...
Locking Enterprise Manager ...
OMS Console is locked. Access the console over HTTPS ports.
Restart OMS.
Restarting Enterprise Manager ...
Stopping Enterprise Manager, this can take some time  ...