when you create custom content with daz, when you save the content out daz deals with the data folder for you based on what you select for vendor name, product and item name.

for textures its not required but the default is to have them under runtime/textures/vendor name/ product/ as long as they are somewhere under the content folder tree when you reference them from daz and save your item then daz should be able to find the relative path provided they are installed to the exact same location under content on the users side. the use of the runtime folder is best though as users may move items around and as long as they don't mess with runtime it should still work fine.

it is common practice to save items under the content folder location that matches their item type, so if it is an item for genesis 8 female, it would go under People/genesis 8 female/ <type of item prop,clothing,pose etc.> /

if its more generic like a prop, environment, lighting, shader it would just go under a folder of that type under content.

so pretty much everything is in a folder path somewhere under content content/type of content/product or vendor name (/product name)

poser is a little different and I don't use it so can't comment much but there pretty much everything goes under runtime.