Kubuntu's new and easy method of installing packages is to use the 'Add/Remove Programs' tool. Click K-Menu → Add/Remove Programs to start it.
Add/Remove Programs is a simple graphical way of installing and removing applications in Kubuntu. To launch Add/Remove Programs, choose K Menu → Add/Remove Programs from the desktop menu system.
To install new applications select the category on the left, then check the box of the application you want to install. When finished click Apply, then your chosen programs will be downloaded and installed automatically, as well as installing any additional applications that are required. The default selection is restricted to KDE suite, but GNOME applications can be installed simply by selecting from dropdown menu at the top. Alternatively, if you know the name of the program you want, use the Search tool at the top.
Software from additional repositories may be installed by enabling the Show: Unsupported and Show: proprietary software checkboxes if they are enabled in your repository list. For more information, see the Repositories page.
Once this has finished, click Close.Your new programs are installed, ready to use!
source :
https://help.ubuntu.com/community/InstallingSoftware