Here, we have a list of numbers. We can use zl slice index, to get two lists, one before index and one after. Thus zl slice 1 will get 1st value of list in outlet 1. zl ecils 1, will get last value in list in outlet 1. (ecils is slice spelled backwards). The are other zl objects, such as zl group size.
Here, we unpack a list of 4 numbers. You can see the left and right sides are similar. Instead of using numbers to display the values, we also use print objects. However, with numbers, we can see the values on the canvas rather than looking at main window. But this assumes the values are numbers, not symbols or lists.