Beginner: What do I do after I've created a case-sensitive disk image?

[Oday]

Hi everyone,

I began trying this out just last night and I'm following the instructions on this page https://source.android.com/source/initializing.html

I'm at the "Setting up a Mac OS build environment" step and I've successfully created the sparse image and am able to mount and umount it successfully. Although I am not sure how to proceed from here, I specifically don't understand this:

Once you've mounted the android volume, you'll do all your work there. You can eject it (unmount it) just like you would with an external drive.

How do I start doing all my work there? The step after that one is Installing the JDK, where do I install the JDK? How do I ...well, switch to that new volume that has been mounted and start working? Because on my /Volumes/Macintosh HD/ where all my local stuff is, there's already a JDK and I already develop for Android.

Thanks for the help