If you get a list of numbers and you want to calculate the sum of squares of that list, you may want to find the patterns of the numbers. For example, if you have a list of (1, 3, 5, 7), you'll notice that these numbers are all odd, which gives you range(1, 8, 2). Similarly, if there is a list of (2, 4, 6, 8), if'll give you range(2, 9, 2).
After that, you make a for loop within that range. You'll need a variable (total) to keep track of the sum of squares after each iteration. After each iteration, that variable total will add the squares of the previous iterations. Finally, you'll get the sum of squares of that list when the loop ends.
You can apply this to other kinds of list as well. To calculate the sum of the list, you'll do the same as if you're calculating the sum of squares. First, you have a list. Then you find the range and loop through that range while having a variable that adds up each time the loop runs.