Just try a bit harder, it's not difficult. If you have basic idea about VLANs (what it is, tagged, untagged), then:
1) If there's only one physical interface involved, then all you need to do is e.g:
/interface vlan
add interface=ether1 name=vlan10 vlan-id=10
and you'll have tagged VLAN 10 on top of ether1 and interface named vlan10 to access it. Now forget about this for a moment.
2) If you need to use more than one physical interface, you need bridge to put them together:
/interface bridge
add name=bridge1 vlan-filtering=yes
/interface bridge port
add bridge=bridge1 interface=ether1
add bridge=bridge1 interface=ether2
add bridge=bridge1 interface=ether3
This step is intentionally incomplete. When doing it for real, remember that wrong (or incomplete/unfinished) config can easily lock you out, so it's best to configure bridge when you're not connected to one of its ports.
3) Then define what VLANs you want, where you want them, and in what form:
/interface bridge vlan
add bridge=bridge1 vlan-ids=10 tagged=ether1 untagged=ether2
add bridge=bridge1 vlan-ids=11 tagged=ether1 untagged=ether3
Simple, right?
4) To slightly complicate it (I don't want to, but unfortunately it's like that), untagged VLANs are not defined exactly as shown in step 3. You can keep it like that (it may be good idea, to clearly show your intentions), but you also need to define untagged VLAN assignment for each port using its pvid parameter like this (it completes step 2):
/interface bridge port
add bridge=bridge1 interface=ether1
add bridge=bridge1 interface=ether2 pvid=10
add bridge=bridge1 interface=ether3 pvid=11
If omitted, pvid defaults to 1.
5) Configuration so far (steps 2-3) was only for router itself not participating in those VLANs, i.e. it acts only as managed switch. Sometimes it's enough. If you want router to participate (e.g. for routing between VLANs), you need VLAN interfaces, same as in step 1. But where to put them? On bridge interface of course, because it also acts as another port:
/interface vlan
add interface=bridge1 name=vlan10 vlan-id=10
add interface=bridge1 name=vlan11 vlan-id=11
But it won't work. You may notice that bridge also has pvid parameter, same as its ports. Which means that by default, bridge interface is untagged access port for VLAN 1 and there are no other VLANs available on it. Which can be fixed by slight modification of config from step 3:
/interface bridge vlan
add bridge=bridge1 vlan-ids=10 tagged=bridge1,ether1 untagged=ether2
add bridge=bridge1 vlan-ids=11 tagged=bridge1,ether1 untagged=ether3
Now you have interface bridge1 with tagged VLANs 10 and 11 (and unused untagged VLAN 1), and interfaces vlan10 and vlan11 to access those VLANs.
6) That's it for basics, THE (happy) END.