linking cells in different workbooks

Hi

I have only recently "converted" to an iMac having spent my previous life using Microsoft so there has been somewhat of a learning curve regarding how things are achieved, specifically in Numbers so if this a rather obvious question please remember I am an iMac virgin!!

I have taken advantage of a number of you tube videos which have been more than helpful but I am struggling with one specific point with which I hope someone can help. I understand how to link the results of one cell to another using the equals key and selecting the information you want by highlighting the relevant cell. I can do this within the same sheet or indeed with sheets within the same workbook/file. However I want to link the results of a sheet in one file to a sheet in another. They are separate workbooks and need to stay as such so it is not a case of copying both into one workbook in order to access the information I want. Clearly it is possible via the paste/link option in Excel but how do I achieve this in numbers? Any pointers or info would be gratefully received.

All the best

Martin