I think it's for the best interest of the installer that you don't add credits for translation. It just doesn't make sense and makes things look messy. Just my opinion. I certainly wouldn't ask for credits if I did a translation.
I am not a fan of reading installation procedures in Bangla. It feels awkward to begin with.
Some of the words just can't be properly translated. Like Navigation, for example. But you've done a mighty impressive job.