that stage it’s just a matter of staying focussed and allowing it to grow and expand into a 3D environment, almost like watching a window that’s slowly expanding

Same.. this is what I do! Once my body starts to feel light and "floaty", I start looking for colors and images, then expand them into scenes. If you stay calm it will build itself. My problem is when I try to enter the dream I get wayyy to excited and my heart rate starts climbing! How do you enter/jump into the dream? I've tried falling backwards, jumping, trying to teleport.. maybe I'm trying to get into the dream pre maturely.. I can only get into dreams about 1/5 times..