Greenhouses can be made of soft plastic or hard plastic. At my workplace we have both. (There is a fancy name for the hard plastic, and I can't remember it right now.) Either one of these plastics is not meant to hold a person. Thus, to walk on the top of a greenhouse means to step on the beams of the greenhouse. The beams can hold your weight and not the plastic.
Well, yesterday I worked up on the roof again walking on the greenhouses. Let me give you some advice on how to do it, though I am not an expert myself:
1) Don't look ahead. Keep focused on the step you are making.
2) Don't rush. Rushing hinders you from keeping focused on the present step.
3) Don't worry about far you have gone or how far you will need to go.
4) As my boss says, don't look through the plastic. That seems to make it a little scarier, and for him affects the depth perception. Stay focused on the beam.
5) Stop and enjoy the view. It is beautiful up there. You get to see a new outlook on life.
6) The last and most important and all pervasive, and I should not even have to write, trust in God.
In other words, be fully present with God in the moment and not in some other moment. If you learn to do that, you will succeed in walking on greenhouses and in life.