Rain-gutters (eaves-troughs) work well as jump-aids for a variety of reasons. We use the jump-aids for a variety of similar purposes which eases learning. I also like their width, their rounded edges and the fact that they don't get caught up in the dogs feet during clumsy moments. They are cheap and easy to move around with one hand. Many people use flyball jumps or modified jumps effectively as jump-aids. Initially, I use three lengths of rain gutter attached together as a pyramid. I want the prop to be high enough that the dog will jump over it rather than step over it.
First, get your dog driving and focused by tugging with him. Know which way you want your dog to turn and stand to that side, so that when the dog turns into you he is turning in the direction you will want him to use for his box turn. Set your dog a couple of feet back from the prop (jump-aid), and call the dog over. I don't want to run away from the prop since the next exercise will involve the dog going over the jump, immediately turning around and jumping back over the prop. If necessary, I will take a couple of steps away from the jump to draw the dog over.
If he goes over, we play tug for a minute. If the dog goes around, I vocally keep him energized with encouragement but he doesn't get the tug. I take him back, set him up, and try again. As soon as he is committed to the jump and can't change course I give a good "YES" or CLICK. For most aspects of training turns I prefer just using a "yes" to indicate when the dog has performed the action which is earning him the reward. That way my hands are free to play. I was taught to use the clicker for situations requiring more precision.
A few good repetitions and the dog understanding the task is all there is to the first session. This step familiarizes the dog with my jump-aid, and at this point I am not concerned about using my tug as a lure. I usually only spend a couple of minutes on this and then put the dog away for a short period to let him think about it and keep up his desire. It is always best to quit with the dog wanting more.
Hup-Again simply adds on to the first Hup exercise but requires much better timing on the handlers part. To start, I usually straddle the prop for this, again on the side of the prop that the dog will be turning towards, with the tug hidden behind my back. Set the dog up, give your verbal cue, use a strong shoulder twist to get the dog over the prop, then bring the tug back over the prop with an "Again" and step back to the side the dog started on. I find it best to keep the tug low to prevent bad habits from forming which would carry over to the ramp work.
Using Celt who turns left as my example, I'll go over it in more detail. I've got the dog set and I'm straddling the end of the prop on the dog's left. I have my tug in my left hand hidden behind my back. I send the dog over and swing my right shoulder forward to make the dog think I'm running ahead of him as he goes over and enticing him to make the jump. As soon as he is over the jump I swing my left shoulder back towards the center turning back in the direction the dog came from, bringing my left hand with the tug down and telling the dog "Again" which causes him to turn left immediately upon landing and jump back over the prop. If he does it correctly he gets to tug, if not he gets encouragement and gets set up again. Don't allow more than two failures in a row without giving him a task he knows and rewarding him before trying again. Expect the dog to second guess you and try heading you off as you turn back before he goes over the prop, it's the intelligent thing to do. Be prepared to keep the tug from him and only let him get it once he's done it right, but don't get upset with him for being smart. Have fun with it. Joke with him if he tries to outguess you. and then try again.
The next video shows me standing further back from the prop. At first, while straddling the jump, I start by using the tug as a lure again, but after a couple of repetitions I wait to see if he has figured out what he has to do to earn his reward. If necessary I alternate between luring and waiting to see if he'll do it on his own and try to keep it fun and avoid him getting frustrated. Once he shows me that he understands, I'll start moving further away from the jump.
Before I move on to the ramp it is critical that I can send the dog to do the Hup-Again while I'm standing well back from the prop and without luring. By spending the time here and doing a thorough job I can move right into developing a technically correct turn when I go to the ramp. If I'm still luring the dog over the prop when I put it in front of the ramp I will have the dog looking up, jumping up with poor foot location and having terrible rotation which I will then have to correct. It is much faster not creating the problem than correcting it.