The fastest way is to use plugins like this one: Easy Theme and Plugin Upgrades

  1. Download the latest zip file for your theme (directly from your TF account). 
  2. Log into your WordPress site. 
  3. Go to Appearance > Themes. 
  4. Click the “Add New” button at the top of the page. 
  5. Click the “Upload Theme” button at the top of the page. 
  6. Click the file browse button to select your theme zip file. The button’s text varies by browser. It typically says “Browse…”, “Choose File”, or “Choose…”. 
  7. Select the zip file with the new theme version to install. 
  8. Select “Yes” from the “Upgrade existing theme?” option. 
  9. Click the “Install Now” button.