How do I change an individual object of a collection instance after the Instance on Points node. For example, I'd like the spheres to be higher in that image. How can I use nodes such as Translate Instances but for just one of my collection objects. My instinct would be to assign the index in the selection but I can't figure out how.
This answer here only serves to complete the range of possibilities...
If the transformation for a certain object should always be the same, then it is recommended to perform it ideally BEFORE the instantiation.
This way, this operation does not have to be applied to a large number of objects, but happens only once, which can possibly achieve a gain in terms of performance:
PS: And by the way, the correct rotation for your instances is provided directly by the node
Distribute Points on Faces.