To accept GRAT tokens on your Stellar account you have to create trust line first:

  1. Navigate to official Stellar Trading Client page
  2. Click 'Login' button
  3. Click 'Login with key' button
  4. Enter your secret key (here you can find how to get you secret key from Gratzio wallet)
  5. Click 'Log in' button
  6. On next page you click 'Accept and Continue' (or 'No thanks' in case you don't want your account will vote for the StellarTerm inflation account)
  7. Click 'Accept assets' on top bar menu
  8. In section 'Accept asset via anchor domain' in 'Anchor Domain' field enter
  9. Wait until it loads
  10. Click 'Accept GRAT'
  11. Now your account ready to accept GRAT tokens.