I've been using a mac for a long time, and I've currently switched to Ubuntu, as my old macs have been obsolete for a while now. I'm working on an old Dell, and do not appear to have hardware issues. The help I need is more basic than that.
Is there a tutorial for Mac to Ubuntu ?
Things I'm sure are simple, but just don't know to look for, like is there an equivalent to "applications folder" in Ubuntu ? Doing just fine with most things, but simple stuff like this is slowing me down. I don't know what, or how many applications are on this computer. I have found some because the software center shows I already have them. I can't fit everything in the launcher- or can I ?
I also would like to know what file compatibility problems I may run into, and what to do about them.
I'm using my back up external drive from my mac. I have transferred my mp3 collection over into Rythmbox, but was having some trouble with some photo files. Seemed to resolve itself when I used a different piece of software.

Thank you for helping out a newbie.