If I create a new list, can I add products to it throughout the week and place the order, for example, on Friday?

Each list you create is completely editable. You can rename it, copy it, or merge several lists. The same applies to its interior. Products can be edited at any time - add and remove, as well as change their quantity. Additionally, editing a list is saved in the list history, so we can see who last edited it.

More information about lists can be found in the "User manual" section 9. Lists, link below:

https://dentametrsupport.zendesk.com/hc/pl/articles/17332085140369-9-Listy