You guys look much better in the second round of pictures! =) He's very cute, what breed?
Okay, so sounds like he does have experience jumping. For you at this point, I'd say get a feel over some x-rails. I know his experience is there, and yours will come. For now just learn to "feel" his stride and jump. I'd also say to shorter your stirrups O/F as is does look like your heal has come up in the pictures - a little hard for me to tell in these photos as a direct side view would help, but I'd say shorten maybe 2 holes? Someone correct me if my eyes are playing tricks haha.
Your release is not bad by any means, but since you are so new to jumping you could very easily catch him in the mouth on your landing (x-rails can help before bigger fences), but a couple strides before the fence I'd suggest placing your hands and grabbing mane where your release should be, keep them there until after the fence.
Overall you guys look like you're on your way to being a great pair O/F! Would love to see some videos as he looks like a really cute jumper =)