You will have to install the font into your Windows before using other symbols and keyboards from other characters sets. The first thing to do is to install the keyboard. If you have the setup package, launch it and install it, then use the FONT you have for the Keraleeyam language/layout and place it in C:\Windows\fonts. Make sure the Microsoft PowerPoint is closed. After the font has been installed, start the application and you should be able to type whatever you need using Keraleeyam layout.