Filter and sort the list until you see the desired subprojects in the correct order.
Click on the 'Export' button (↓).
Enter a description of your export.
Select the desired export template.
Click on 'Export subprojects'.
Your export appears at the top of the page with an overview of all the exports of the type 'Subprojects'.
Refresh the page until you see the number of rows next to your export.
Click on the description to download your export file.