You need to attach your Array to the Get node before it can read the variable type so that you can split out the particular members. Also the same as dragging off of the Get node and using the Break node.
Just as a side note, you need to break any connections to the Pins before you can either Split or Recombine. Just something to keep in mind, Break Nodes do have their uses, though i hardly ever use them haha.
Yep splitting the struct pin came along with 4.7 and is a huge cleanup on breaking structs apart all the time. Setting vectors through floats is a prime example of this 1, I much prefer to just split the input 1 and plug the floats straight in rather than have the 3 floats go into a make vector then plug that in.