Business Diploma Help!

I'm currently doing the exploring business purposes first diploma, Unit one Assignment three and i need a bit of help..

i have been asked to..
write a letter to your client which must include the following advice:
- a description of the difference between aim and objective
- Examples of common aims and objectives that businesses might set
- An explanation of the main purposed why a business should set aims objectives

IF anyone could provide links for help on this it would be very helpful, or if u have any ideas and would just like to post them, feel free it will be most welcome

thanks in advance,

Stefan (Y)