There are two main schools of thought about a tanks job in RvR. Some players feel that tanks should stand in the back and try to protect healers, and other players feel that tanks are front line assault warriors who should charge into groups of other players and get aion kinah. Let us say then, for the sake of argument that a Swordmaster role in RvR is to act as a front line assault element. Their high mitigation and ability to spec for very respectable damage makes them very deadly in this role. With proper healing, a Swordmaster can charge into a full warband of destruction and take them all out one by one without risk of dying. Without healing, they can still survive long enough to create an opening that the rest of the Order players can exploit.
Exact descriptions of all the abilities, tactics, and morals that you can get as a Swordmaster have been done by other players to a much better degree than I am able in this aion gold guide. For example, the Wards database has a very nice listing of all the skills and how they change with level. I will therefore not repeat their work. Instead, I will give a few short notes on the various skills and their uses.