Is there any simple way to access installed programs?

ClassicMenu Indicator will do the job!

• To install it, open a terminal with Ctrl+Alt+T, and type:

  sudo add-apt-repository -y ppa:diesch/testing
  sudo apt-get update
  sudo apt-get install -y classicmenu-indicator
  

Just like "Applications" on the Mac, you could browse "/usr/share/applications"

The best way to get there is open "Home Folder" or "Files" from the dash, press '/' and type '/usr/share/applications'. I guess you could make a bookmark there by pressing ctrl-D.

This is something way too easy,i do not undestand what is difficult for you to find.

For Gnome:

Applications -> All your software seperated in categories

System - > System tools

Places -> Folders

For Unity:

Click on "Dash Home" at the top left corner of the sidepanel:

Then search for the program you want to open: