I just want to add amounts in a column eg. b7 to b15
Trying not to assume too much from the wording of your question, there are several methods that you could use, but
=SUM(B7:B15)
is probably the most straightforward and easiest to understand. You could check the help file to see other possibilities.
More details.
Using the SUM function would help you. Which is what @ve3oat suggested 
Are you having an issue with that working? Some people are trying to add a range like that and getting zero. (i’m one)
Usually it happens when cells contains numbers as text not true numbers, for those only direct references works, not ranges.
So, in “direct references” method: =B7+B8+B9+B10+B11+B12+B13+B14+B15.