I've set up Prestashop multistore according to the Prestashop docs. My main domain is margaretdabbs.nl and the other store that I want to manage from this backend is aspadirect.nl/shop. However, none of the guides that I've seen explain what you should actually do on the other domain, they only said what to do for the existing PrestaShop installation.
So my question is: what do I need to do on the other server? Should I install PrestaShop there as well? Set up multistore in the same way?
Or do I need to point the aspadirect.nl nameservers to the original domain (margaretdabbs.nl) and do some DNS-fu?
Answer on your last question: yes.
Detailed: the main idea of multistore it is "One back-office to rule them all". You have one Presta installation on one server and can manage multiple shops (with multiple domains or just different uri's) with different or same products/categories etc.
In your case both domains should be bound with same IP to have possibility manage them as multistore from backoffice on margaretdabbs.nl. Also if you have 1.6.x Presta new docs.