Need help with how to write a loop function...

* Data in a list is in column A on Sheet1 - the number of entries in the
list may vary

* Starting from A1 on Sheet1 I need to copy the value and paste special the
value to Sheet 2 cell B1 - there are calculations that run based on the value
in B1

* I then copy a range from Sheet 2 and paste special to Sheet 3 - this part
I know how to write code for

* After the copy / paste of the range from Sheet 2 to Sheet 3, I need to go
back to Sheet 1 and select the next item in the list in column A - this would
be A2 in this example

* Then run through the copy/paste from Sheet 1 to Sheet 2 - run the
calculations - then copy/paste range from Sheet 2 to Sheet 3

* Repeat until the last record in the list in Column A on Sheet 1

THANK YOU IN ADVANCE!!!!