Creating a .dmg + a couple of other questions

I am really sorry to be such a derp, but I truly, honest to the Flying
Spaghetti Monster cannot figure this out. I have been reading the
previous topics, incl. stickies, and I cannot find the guide to making a
.dmg file. I can find fixes and common errors, but no guide to how to
actually make the damn thing. The answer is no doubt obvious and I have
just made an idiot of myself, but... can I have a link?

Also, my gf has TS3 installed from the original disk, do I need to
reinstall that for her, or is it okay to just go ahead and install the
expansions from here (once we've figured out how to make disk images of
them)?

And lastly, do we have to install Generations first as per guidance, or will it work fine if we just proceed to Late Night?

Admin edit: Topic moved to right section.

- ADMIN

http://games4theworld.org/index_files/Torrent%20files/The%20Sims%203%20MAC%20Guide.pdf

&&

Install generations lasy