Hi dale..welcome mate....
Mix the grout up to a good texture..don't mix it too wet..grout then leave to set for a while....the trick is when washing off is to apply light pressure so as not to remove it from the joints....we use washboys and these cleaning tools leave a very neat finish....here is a pic of a tilers washboy....supplied by our forums tool sponsors...
wash the tiles once and leave the grout to set longer again before final clean up....hope this helps dale..good luck...