Ubuntu 12.04 64 bit

I have favoured software applications such as Dolphin , also Kate.

On the left hand of the Desktop screen are 7 application ikons. (I ervicted the ones I'll never use)

I would like to add more. But knowing that an application is installed from information in 'Ubuntu Software Centre' does not seem to lead to any way of running that application or adding it the colomn on the left hand side.

Am I mad, ? what obvious thing have I missed? is it all done in Bash from the Terminal ? (After a struggle I found out how to get that running !)

An thoughts very very welcome,

A struggling,