You need to make sure the handle is in the "carry" position first. Then grasp the carry handle with one hand and use your other hand to lift the bassinette release catch (I think that's the blue button?). You should then be able to lift the capsule straight out.

Do you have the instruction booklet? It will tell you how to do it in there, otherwise you can download the instructions from their website.

I don't have a Unity capsule, but I've sold them in the past and they're pretty user friendly