Weighted percentages on gradebook spreadsheet

I honestly don't have any idea what I'm doing. The most I have ever done in Excel was to fill in a previously-written form for expense accounts, several years ago. It was basic, and had few functions other than adding up small expenditures, and removing that amount from the overall balance.

I have a gradebook spreadsheet that was supposed to let me enter grades, and give a value for weighting the grades to make the final overall grade come out correctly. The documentation that came with the free download was written for people who seem to already know what to do, and was thus not very helpful.

An email to the people who wrote it simply came back with the instruction 'check the documentation that came with the sheet you downloaded' so apparently, I am too simpleminded to get this.

Across the top of the spreadsheet is a row of "Assignments" and a "point value" below each assignment, but I have no guidance to know what point value to enter to match the weightings I have for each type of assignment.

In my case, Quizzes are worth 30% of the total grade. There are 13 quizzes.
There are 4 special assignments worth 20% of the overall grade.
1 research paper worth 15% of the overall grade.
2 exams, worth 20% of the overall grade. (Midterm and Final)
One special project worth 15% of the grade.

How do I figure out what each of the assignment types should be worth to know what to enter into the spreadsheet to make the final grade come out correctly?

I have attached a screen shot of the spreadsheet, to show what I'm talking about, with the "points" cells highlighted in yellow. What "point values" do I put in the yellow boxes?

Can someone give me some advice?


Grade Spreadsheet

send the file - it will be

send the file - it will be much easier to understand the formulas.