public int getSmallest4(int[] nums)

Given an int[] array with 4 elements
return the smallest value.

Create an int return variable called smallest.
Assign it a default value, e.g. the first element.

Use an if statement to check if the 2nd value is smaller -
and if it is smaller, change the value of smallest to that value.

Use ANOTHER if statement to check if the 3rd value is smaller -
If it is, change the value of smallest to the 3rd element.

Use a 3rd if statement to check if the 4th value is smaller -
If it is, change the value of smallest to the 4th element.

public int getSmallest4(int[] nums) {
  int smallest = nums[0];
  if (nums[1] < smallest) {
    smallest = nums[1];
  }
  if (nums[2] < smallest) {
    smallest = nums[2];
  }
  if (nums[3] < smallest) {
    smallest = nums[3];
  }
  return smallest;
}

Below is how you would do the same thing using Math.min().

public int getSmallest4(int[] nums) {
  int smallest = Math.min( nums[0], nums[1] );
  smallest = Math.min( smallest, nums[2] );
  smallest = Math.min( smallest, nums[3] );
  return smallest;
}