I have tried it a couple of times in the context of Mahamudra-style shamatha, from a cd by Reggie Ray, so the end result was not expected to be any of the rupajhanas, as far as I understand.
Can anyone in detail tell me how that is done?
In my experience and from what I have learnt from other meditators, there is always a big degree of personal taste and inclination in how one applies a certain technique to reach the jhanas. If you already have some mastery of the jhanas, you can usually apply another person's favourite technique and get there all the same, but for the first few times, it is mostly a matter of finding out what works for yourself. All the examples you make seem like excellent potential candidates for entering jhana to me.
In the following I will assume that you do not have some degree of mastery of the rupajhanas already. Apologies in advance if this sounds too simplistic.
Imagining energy or a white light?
Sure, it can work, but it is not necessary. It might be a tree, a flower with a fragrant smell, a big exciting ocean wave, a small refreshing ans soothing caribbean or mediterranean wave, nothing at all...
In and out of the body synchronised with the breath?
Seems like a nice mental image to work on.
Do you need to visualize it that way on a body as a whole?
If you like, yes, absolutely. But, depending on your inclination, you might have better success picturing it on your hands, on your feet in your heart region, on the top of your head, in the third eye region...
Or do you actually imagine on an inhale breath/energy going in from the head and then moving attention to the chest then legs?
It can work. I usually go the other way around:
inhale = up from the base of the spine and/or from my skin up through the back of the chest, spine and neck all the way to the top of my head,
exhale = down through the chest in the arms and legs.
Entering first/second jhana is a feeling of "accumulating pleasure/energy" at the crown of my head and/or in the third eye region. Other good friends of mine do radically different stuff with pretty similar results.
To put it in other terms: Whatever works. Find a combination of images and/or feelings that capture your attention and your imagination (that should get you vitakka & vicāra naturally) and that you find pleasurable, soothing, exciting, rapturous, blissful (leading as easily as possible to pīti and sukha). Start a feedback loop on whatever seems to work for you. Feel free to pay around with whatever inspiration gives you.