1. Open "Control Panel"
2. Click on "Region and Language"
3. Select “Keyboards and Languages” and then click on “Change keyboards…”.
4. Go to “Add” and select Bangla (Bangladesh).
5. Press “OK.”
Now you can just select the Bangla keyboard from the language bar on your desktop and start typing in Bangla.
If you can’t see the language bar on your desktop, "Enable Language Bar":
6. Right click on the Taskbar
7. Hover over “Toolbars”
8. Select "Language Bar."