Please read this article on how to setup the MT.
http://forum.mikrotik.com/t/using-routeros-to-vlan-your-network/126489/1
Basically you create as many vlans as you need,
create them with interface being the bridge.
Assign ip pool, ip address, dhcp server, dhcp server for each vlan
Then assign bridge ports (ether1 the wan does not go on the bridge).
ETher 2 is on the bridge as a trunk port.
ether 3-4 can be use for anything you wish to a pc or to another switch etc…
ether 5 you may want to keep as an OFF the bridge, emergency access to the router in case the bridge config goes squirrlly on you.