He's so far away from walking out calm as a cucumber that I just don't see him getting there without a lot of help. He may need quite a bit of hand holding before he's going to be truly calm about going out. Having a buddy, being praised for just putting one foot in front of the other in the asked for direction (which is what you want him to do regardless of how he feels about it), and a rider who will both support him and catch him before he bolts. Which is why I think the OP should get help since at this stage she has not accomplished the last part. Calmness will come later with experience and confidence.

I'm saying all this on the assumption that he's a nervous nellie who deals with being scared/confused/overwhelmed by forward motion. It's my horse's preferred method of avoidance and dealing with problems (go go do not look back!) so maybe I'm biased. Praising her for doing even the slightest thing right really boosts her confidence. But I've always caught her before she really takes off.