Postgresql how to group the values in on column of a table and transpose the unique values of another column in the same table, and sum up the rows

Question

I am new to SQL in general, hence this problem is a little tricky to me. I have a table like the example below:

Input Values:

And, I wish to get the following output:

Output Result:

Honestly, I have no idea how to begin to solve this problem. I would appreciate a hint and/or an example solution from anyone. Thank you in advance.