Stupid question... But how to zoom in

Hello!

So sorry for a dumb question... But I just got a new computer, and after playing total war games on my old laptop for 6 years I now have a new computer with a completely new keyboard. And for the life of me, i can't figure out how to lower my perspective of the campaign map from the overhead view down to the more zoomed in.... I don't have the plus key that can be combined with the FN button, and am wondering if theres a manual way to do it? I have a lenovo thinkpad...