QoS question

Dear Mikrotik users,
I have 3 questions,
1- how can I mark upload and download traffic seperately for a specific user in mangle?
2- can I send the user’s upload traffic to a gateway and the download to another? is this possible?
3- in Queue Tree, do I need to have a parent rule and a child for qos to work, or I can just create one rule and apply limitations accordingly?

thanks.

bump