Please don't. The way trusts(and squadrons) work, you will likely learn bad habits. The NPCs don't AoE or use positionals, you also don't really need to worry about them taking AoE damage.
Just learn normally by running low level dungeons and moving up to the later ones as you level - you will learn to tank much better with real people and you might even get some good tips from more experienced players as you go. You shouldn't be afraid of complaints - most people either won't speak or will be nice even if you mess up, especially if you apologize.