For anyone who is even a little claustrophobic bondage becomes a tricky deal. In my experience though if you keep the bindings all in front so they are visible to her this really seems to help. So wrists only tied in front, soft rope is also good as it's more comfortable and less scary than things like metal handcuffs. The soft, velcro type wrist cuffs also work ok but try to avoid anything that looks or feels harsh.
You have to remember that a lot of what you do in bdsm is creating a headspace so how things look and feel is just as important as how they're used.
The body harness (
was it the one I posted here?) is a good idea however be sure to keep the wraps around the upper body at a reasonable tension, just tight enough to hold the shape as that chest constriction can feel a bit weird to some people.
You also probably want to stick to lying upwards on a bed, sitting or standing to begin with, avoid kneeling and anything face down or where vision and/or breathing may be impacted. I have a
primer here on using rope that covers pretty much everything you need to know about getting started.
A few of simple things worth trying out,
- A chair tie, sitting in a chair with arm rests tie down wrists to the arms and feet to the legs
- Classic spread eagle, on a bed wrists and ankles pulled to each corner
- Sitting on a bed, tie wrists to ankles then spread to bottom corners
- Lying near the edge of a bed, knees up, tie wrists to ankles and spread
A useful addition is a spreader bar, can be used for feet and wrists and makes spread ties simpler.
And finally stay safe, ensure you have good strong scissors on hand (bandage scissors are best, you'll find these in the primer I linked) as you never know when a knot will get overtight and refuse to undo. It's also a lot faster if panic does set in to cut the ropes off quickly, speed is vital to prevent it getting out of hand.
I'd also suggest you both read up a bit prior to getting into things,
this one on consent will fill some gaps you might not be aware of and this
safety discussion cover pretty much everything you'll need to get going.