Solution file and webpart files are in sharepoint 2007 and i need to upgrade it to the sharepoint 2010 version

Question

Hi

Thanks in advance ..

Solution file and webpart files are in sharepoint 2007 and i need to upgrade it to the sharepoint 2010 version 

I have a solution file and webpart file in sharepoint.how to open those file? where to open ,which file to open in which environment ? 

what process has to be done to make upgrade?