Should I make the first move?

I started to notice a coworker of mine admiring me from afar and having his eyes locked in on me the moment I enter the building, so because of that my thoughts of him shifted to being interested in getting to know him more. He is starting to warm up to me more by waving and saying hey, but he is really reserved so it never goes beyond those interactions, I want to express my interest in him but I don’t want to come across as pushy or weird. How should I approach him?
Should I make the first move?
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