I have a newborn and I put her in a bassinet I want to try using a sleep sack/love to dream swaddle up, do I still need to place her at the bottom of the bassinet or is the middle ok even when there will be no other blankets or bedding?

Have you been wrapping her up to now?
Why did you want to change to a swaddle suit like love to dream?
A sleep sack is one that has arms out, a swaddle suit has arms tucked in (like a swaddle)

We generally recommend placing them feet to foot of cot or bassinet, to reduce the risk of head/face being covered.
If there is no bedding then there is no risk of head/face covering.