Mac Partition, how to allocate more memory to windows

I originally read a thread on the allocation of memory advising the use of EaseUS. After downloading and attempting to use the software, it appears to believe that the mac side of my computer has a full memory (which is far from the truth) and therefore doesn't allow me to allocate any extra memory to the windows partition. I'm not particularly technical, so it would be preferable if answers are understandable, thanks.