Unable to browse a .txt file from local mechine to upload in web application

Hi,

 I am new to the telerik test studio.I have to develop a automated test script for a web application.But, here I am facing a problem regarding browsing a .txt file from local mechine and upload it to the web application.In the application , a browse button is present.We need to click on this button >  select the particular file and upload it.Can you please help that what code should I need to use for this purpose?One thing , I need to mention here, that, I am using vb.net.