To export members, you can go to 'Members' in the menu:
Either select all your members by clicking on the square next to 'First name', or you can use the filter function at the top left to filter down to a smaller target group.
When you select the members you want to export, an 'Export' button will appear.
When you press 'Export', all the information that you have stored on the selected members will be included in the Excel sheet.