...
Click Manage Jenkins > Manage Plugins > Available.
Select MultiJob.
Click Download now and install after restart to automate the downloading of the MultiJob plugin, and installing it, and then restarting the Jenkins server.
Click Manage Jenkins > Configure System.
Enter the number of executors you want, in # of executors.
Click Create Job, andselect MultiJob Project.
Click Build > Add build step > MultiJob Phase.
From the Job Execution Type list, select Running phase jobs in parallel.
Click Build to run the MultiJob Project job.
...
The parallel execution of offline packages
...
start.
...