how to convert a project for multiple language like english to arbic using c#

for asp.net follow bellow link
http://www.codeproject.com/Tips/644196/Create-Multi-language-ASP-NET-Website

and: it is a terrible lot of stupid ***manual*** work (even when you have tools which allow for some of the steps to be automated).
string concatenations are a bad issue, you have to identify them and replace them with string.Format before. You'll be glad when you have finished that project...