Ok thanks. I’ll make tutorial for it too. here are quick steps. Download ttf font from here : http://www.fontsquirrel.com/fonts/open-sans .
There are many variations but we’ve used in this theme are :
1. OpenSans-Regular
2. OpenSans-SemiBold
3. OpenSans-light
After that go to webfont Generator : http://www.fontsquirrel.com/tools/webfont-generator
Upload these ttf file and after uploading click on the expert mode there here is settings you might want to have : http://i.imgur.com/tcIc98c.jpg
You can choose language support for others too if you want.
After downloading, you’ll have zipped file which will have CSS and all the web fonts there.
I hope this will help you 🙂