ecart rules
I am trying to set up an online store for selling wine. We are wanting to only sell the wine in multiples of 6 and then subsequently provide a 15% discount to this total.
I understand that I need to write a rule which disallows purchases other than multiples of 6 but I don't know where to begin with writing rules for this? We would also need a note to come up letting the customer know that they haven't selected the correct quantity of wine, if they were to try and make a purchase that didn't fit this requirement.
Again, I don't know how to incorporate the 15% discount once the customer has met the above requirement?
I am completely new to the ecart system and online stores as a whole so sorry if I haven't provided enough information.
Any help would be appreciated!