If you can’t see bangla properly in this site then you may not have proper unicode bangla font in your PC. Don’t worry just go here, download it, and paste it in your font folder. Oh must copy the font file before paste yeah Thats simple!!!
To install this font in Ubuntu download the font from here to your Ubuntu desktop, then type in the terminal
cd Desktop sudo cp Vrinda.ttf /usr/share/fonts sudo fc-cache -fv
If you are looking for help with Bangla Typing then you can take a look at here.