Don't feel anything is hid. Linux does not use extensions(file type) to
determine if a file is executable as is done with Microsoft products.
This opens up possibilities to developers that are not found with the
expanded DOS platform used in windows.

I like "application finder" when I can't remember the name of an
application. You can find it in the dash (top icon on the launcher bar).
then start typing in the name application finder and it will show up.

We are here to help reduce your frustration as you migrate to Linux, so
ask away as needed. Then as you get stronger with Linux start answering
others questions as you can.