Hi,
I am doing an Api call (using /rest/v11_8) to get metadata from this endpoint "/rest/v11_8/metadata?type_filter=modules&module_filter=Activities" this is for "Activities" module, here I am getting a response like this 
(image= metadata API response) . Here for simple fields like id,name,date_modified etc we have types as id,varchar and datetime etc. But for some other complex fields like modified_user_link , created_by_link which are objects in the actual API response 
(image= actual api response) has a type as "link" in the metadata api response 
(image= metadata api response ) .
1). I am trying to understand what does this type link actually means and how in the actual API response we are getting the fields inside modified_user_link . There is also a "relationship" field in the "metadata api response" which tells there is a linking between two modules over this field. But there is not much clarity from where the data is coming inside modified_user_link .
2). Also there are arrays that are there in the actual API response . 
(image= actual api response for Accounts module) whose type in the metadata API response is "relate","email" or even the field name itself (for some fields)
(image : metadata api response for accounts module).How do we know what fields should come for the arrays .
3). I am trying to build metadata using the metadata API(/rest/v11_8/metadata?type_filter=modules&module_filter=Accounts) , So needs some clarity related to these complex fields (by complex fields I mean Objects and Arrays) modified_user_link ,created_by_link etc.
Please respond with suggestions
Thankyou