Hi, I am trying to do a tax for my small business. its sole proprietorship. I have all the data on quickbooks and all expense already assign to schedule C

don't know what version of TurboTax you're using but generally, click on the word file, then import, then from accounting software, then select Quickbooks (evidently TT can only import from QB versions 2014 to 2020), then continue. QB must be installed on the computer you're using.  once done you'll need to review schedule c because some things do not come from QB.