You will get this achievement eventually if you are going for
The Explorer achievement in WRC 5 (Xbox 360) worth 78 pointsFinish all the Special Stages in the game in Quick Stage mode.
But if you want this right away, just choose Solo - Quick Stage. Choose your stage. To make it easier you should start at Rallye Monte Carlo since its the first race and choose the first stage. The good thing about this is when you finish a race and return to this menu, whatever rally and stage you just raced will already be highlighted by the little green box. So start the first race and as soon as the race starts and you have control of your car, pause the game and choose give up. The game will automatically give you a time in the race and finish you in last place but it will still count as finishing the stage. Now simply return to the Quick Stage menu, scoll over to the next rally on the list, choose the first stage, and repeat. If you follow this way and choose the rallies from left to right, you will unlock the achievement after your race on the Wales Rally GB.