all possible combinations of k with lists of size n

I want to get all possible combinations of size K from a list of size N.

I have a list with "person" objects and I am trying to create a new ArrayList which will be filled with the list of objects. Each table will be a different combination of "person" objects.

A simple example with numbers is: from a list containing 1,2,3 I want to get an ArrayList that looks like this: [[1,2], [1,3], [2,3]]I wouldn't mind if it looked like this:[[1], [2], [3], [1,2], [1,3], [2,3]]

Here is my code:

public void combination(List<Human> people, int k, ArrayList<List> result) {
    if (people.size() < k) {
        return;
    }
    if (k == 1) {
        for (Human hum : people) {
            List<Human> combinations = new ArrayList<Human>();
            combinations.add(hum);
            result.add(combinations);
        }
    }
    else if (people.size() == k) {
        List<Human> combinations = new ArrayList<Human>();
        for (Human hum : people) {
            combinations.add(hum);
        }
       result.add(combinations);
    }
    else if (people.size() > k) {
        for (int i = 0; i < people.size(); i++) {
            List<Human> combinations = new ArrayList<Human>();
            combinations.add(people.get(i));
            result.add(combinations);
            combination(people.subList(i + 1, people.size()), k - 1, result);
        }
    }
}

The last method I used is on this site for reference: https://hmkcode.com/calculate-find-all-possible-combinations-of-an-array-using-java/

Currently, I am getting the correct number of results in my new ArrayList but each one inside the list is made up of a single one.

I highly suspect the problem is at the end else if, as I have a hard time understanding recursion.

Please feel free to ask any questions or suggest anything else to achieve this.