Who moves the figures in a constellation (both virtual and face to face)? The facilitator or the client?

In principle, the client moves the objects.
Certainly in a face to face session.
In a virtual session, if they do have constellation objects and you are working from their set, than they move them.
In a virtual session, you can also use your own constellation objects and ask the client to guide your hand (as you saw Paul do in last module)

Are the questions that are better suited to be constellated than others? Some questions are off limits, we understand that, but are there questions that are too broad e.g. what do I want to do with my life? Are there questions that do not work to be constellated, because they are too vague or not helpful?

I wouldn’t say that there are questions that don’t work to be constellated.
But we spent quite some time in finding the right question.
A validation we would do is whether they have the mandate to ask this question.
Another question you could ask, to validate their question is: ‘what would be a first step in that direction’, or ‘how will you know when that is achieved’.

When you think about who or what you can move in a constellation, how do you know if the person has the influence to change the position of someone else? (if the rule is that you can only move people in the constellation that you can influence)

In principle you are indeed validating whether that is a move that is possible. I can want that my parents turn towards each other, but that is not going to happen.
You can always move yourself.
If you want to move someone else, then do it very very slow.
Both the client, and the facilitator, or at least the facilitator (when in the right stance) will notice in their bodies whether that is ‘allowed’ or not.
So it is not strictly about ‘influence’.
By moving yourself, you could also check with the client whether they feel that with that move, someone else would be able to move as well (you don’t necessarily need to do the move).

This pertains to the order in which people enter into a constellation: Do you enter the client first into the field when the client is part of the constellation?

That depends on the question.
If your client’s question is ‘what is my place in this system’, then you constellate them last.
Otherwise, if there is a certain hierarcy or order, than you follow the order.
If there is no obvious order (imagine a question that relates to the relationship between 3 girl friends (with no obvious order), then I would ask who they intuitively would position first. And then I become curious, later on, what makes them place that person first.

How are the systemic principles at play during the constellation? How do you use them? Are we asking ourselves the principle questions during the constellation, or are we asking the client at some point during the constellation?

We keep the systemic principles in the back of our mind. Some are very visible, or can be, in a constellation, like connection and inclusion (and exclusion), and also order. Purpose can be. Exchange is less visible, but can come up during the conversation. We don’t ask the client about the principles, but we might ask some of the systemic questions.