Reg If then else.

Hi,

The below os the output required.

If created date-Posting date<5 then output should be at Date difference Group column  is <5

else if created date-Posting date<=15 then output should be at Date difference Group column  is 5-15 days

else if created date-Posting date<=30 then output should be at Date difference Group column  is 16-30 days

else

.....

I have converted created date and posting date into Date KF's but dont know of how to implement if then else

in Bex.Can anyone help me out.