Scheduler Usage

I'm totally new to ctrl-m. I have few ctrl-m jobs already scheduled but now one of the job is dependent on some other job. Now that job needs to be added to these already scheduled jobs.
Lets say the scheduled jobs are JobStart>>Job1>>JobEnd. Now I need to add a job before Job1. Which has to be like this.

JobStart>>(Job_to_be_added)>>Job1>>JobEnd.

What do I do now? Also these jobs are scheduled in production. How do I move it to Test for making the changes? I'm using Ctrl-m 7.0.0

In controlM desktop:
- define the new job
- disconnect the two jobs that must precede and follow the new job, deleting the condition in the condition panel of two jobs involved
- link the first job to the new job and the new job with the fhird, using the mouse (click on the first job, drag on the new job and release; repeat for the second to third job).

Regards