How do i install Civilization IV on my macbook?

I tried to install it, but it says i need to free up disk space. How do i do this?How do i install Civilization IV on my macbook?
You have two options:



1. Delete some programs and games you do not use anymore.

2. Go to the MAC store and purchase more memory for your computer.



Your computer has a limit to how many things it can install. Memory can be pricey, so try to delete some old programs first.