Make sure the program was successfully installed by opening the software center and searching for the program you have downloaded. If it gives you the option to remove the program, then you are certain that it is installed. If it still gives you the option to install it, then do that now.
Since you have upgraded from Windows, press the Windows or Super key on your keyboard to open the dash.
Then start typing the name of the program that you installed, or the file type that is associated with it and it should appear in the search results. Select the program from that list to start it.
After you have accessed the program you can simply right click on the icon that is on the side of the screen and select the option to lock it to the launcher panel.
Hope this helps