My rover 214 cabby, it turns over but wont start since i changed my battary?

I recently brought a 214i cabby and it is in perfect nick apart from the fob has never worked, i have the left right 4 digit thingy which stops the light flashing, but the car will still not start, does anyone know if there is something im ment to do or check when changing the battary, or dose anyone know the proper guide to do the left right thingy. any suggestions will be great my email is mwells86@hotmail.co.uk, or please leave a comment