Need help on this practice for Computer Science final

My computer science teacher said if we could do this assignment we would not have a problem on the programming final. The problem is I don't really know how to do this. This is a basic computer science class for Java. If someone could write the code and a short explanation. I would really appreciate it and it would help immensely. The assignment: Create a Java program that allows a user to calculate their final percentage and their letter grade in this CSC 200 class based on their scores for each graded activity. The user will be prompted for the score of each graded activity. There are 7 graded activities in this class. They are Concept Test 1, Programming Test 1, Concept Test 2, Programming Test 2, Programming Project, Concept Final, and Programming Final. Every time a user enters a value for one of the graded activities the program should check to make sure the value entered is a valid score for that graded activity. Every time a user enters a value for one of the graded activities the program should check to make sure the value entered is not less than 0 or greater than 100. If it is less than 0 or greater than 100, the program should print an error message and prompt the user again to enter a valid score for that activity. The user will continue to be prompted for a score until the user enters a score between 0 and 100. After all the scores have been entered, the program will replace any lower score(s) from Concept Tests with the one from the Concept Final. Then the program will replace any lower score(s) from the Programming Tests with the one from the Programming Final. Then the program will calculate the final percentage in the class based on the relative weight of each the activities. All tests are 10%, Programming Project is 20%, and each Final is 20%. Finally, the program will determine which letter grade the user should receive based on their final percentage in this class (90-100 A, 80-89 B, 70-79 C, 1-69 D, 0 F). The program should end by printing the final percentage and the letter grade associated with that percentage.