It is nice to record the sessions because watching them is educational. But, I started our program without. We discussed the cases immediately afterward, when what happened was fresh in everyone's mind. But, if you're doing group sessions, participants may not pay attention to what others are doing and therefore do not learn from seeing the others. If you have one on one cases, participants may be nervous and remember the situation as "just a blurr". So, I would suggest video recording. You can do it with a camcorder or a laptop and webcam placed at the head of bed. The laerdal aVS system can do this and is not too expensive. If you keep the recording system on a cart, you can take it with you to different locations for sessions. This is one of the simplest ways to get recordings.
As for everything else, I started with deciding what sceanrios I wanted to do. Then, I purchased what equipment I needed to make the situations as real as possible. Starting with selecting scenarios narrows things down. As you add scenarios, you cacn add equipment and supplies to your program.
We have control rooms so that we are not leading or influencing the action. We want our simulation to really be student driven. However, you can be in the room with participants if you don't have a control room. I would suggest that you lay out the rules of your participation in advance in that case. (i.e. weather or not participants can ask you questions, who is in charge of the patient and decisions during the case, etc.) I would also suggest that you are in character during scenarios if you are in the room. You can be a family member of the patient, a house supervisor completing forms (evaluations) during code cases, a CNA or "housekeeping" during other cases. Dress the part too. If you want to speak through the mannequqin it is not realistic when you are in the room, so I would recommend even just having a hole cut in the wall of your sim patient room with one way glass put in (you can buy the film for $40 at Home Depot and apply it to regular glass) that you can sit behing with the control computer on a desk if you are doing that. Make sure the hole is placed where you get the best view of the action. I think the HOB or FOB is better than the side of the room because students standing at the bedside block your views there.
When you are outside of the room, another advantage of video is that you can capture things you might otherwise not be able to see. If you have pan tilt zoom cameras, you can catch the details of care. We like to zoom in when a student gives an IV medication and discuss the technique after the case.
I hope this helps.