Basic line continuation in R

I am trying to break up R code into two lines and having trouble, I think because I am on a mac

For example, just creating a column vector

z <- c(2,4,5,6)

and splitting it between the 4 and the 5

I believe in windows hitting shift and enter would put you in a new line with the additional + (the plus that shows it is a new line). But hitting shift and enter on a mac, is the just the same as enter

control, shift, and enter creates a new line but doesn't have the + so it is not working. Adding + myself is not working (it is considering it addition and not the + for continuation)

Could someone let me know what I am doing wrong?

Thanks