Making assemblies within SW

[indoruwet]

New to SW.
Can draw/create detailed parts.
Having trouble with *making assemblies* - mating parts.
Is there a *trick* so parts will go together easily,
rather then having to rotate/move all the time ?
For instance, is there a sequence *secret* ?
How do you mate two parts, where you know, two surfaces must mate,
but they must mate at a specific distance from the edges, any edges ?

TIA

[seon]

Check the online tutorials.