Hi Dee, the steps are as follows:
1) Go to "My cart"
2) On the top of the page, click "By spreadsheet", a box will be expanded
3) Under the box, click "export cart"
4) Save file as spreadsheet
If you still encounter difficulty in exporting the cart, you can just send me your list. Example:
1) H20-1095PK x 1
2) H20-2407PK x 2
3) ....