Hi
He landed in France on 29/12/1915 so he just got in in time to qualify for the 1915 Star.
He started off in the Welsh Regiment but later became unfit for front line service but was still able to help out in other areas so he was sent to the Labour Corps. He later became unsuitable for that work so he was discharged and awarded a Silver War Badge to prove to everyone back home that he'd "done his bit".
The star symbol next to his 3rd number is what would be stamped on his medals.
For information on the Welsh Regiment, have a look here
http://www.1914-1918.net/welsh.htm especially about halfway down in the Service battallions as some of them match his arrival date in France.
And some background on the Labour Corps
http://www.1914-1918.net/labour.htm