Move first and last element of the RecyclerView to the center of the widget

Question

How move the first and the last element of RecyclerView to the center of the widget?

Example

I found next example: RecyclerView allow first/last items to be scrolled to the centre

But i can't describe this solution for my case. There is my code:

class CustomLinearLayoutManager(context: Context): LinearLayoutManager(context , LinearLayoutManager.HORIZONTAL, false) {
    override fun getPaddingStart(): Int {
        return width / 2
    }

    override fun getPaddingEnd(): Int {
        return paddingStart
    }
}

I feel that I have implemented incorrectly this solution

Please let me know how correctly to realize move outermost items to the center in horizontal RecyclerView widget.