Teleporters are basically used only by the attacking faction, so here's the deal. Once you enter TW instance you cannot use the teleporters. Along all 3 roads (A, B, C) there are stations where towers can be built. Next to these towers you can see pillars (a red and a blue one, one on each side). When you speak to the pillar of that shares a color with you (red if attacking) you can set a teleporting spot. If/when you die you can simply teleport from base to that pillar by using the teleporter in base. The teleporter in base basically looks like a big glowing red circle with two rotating crossed swords inside it. You can see it once you respawn on your right side. The IMPORTANT thing is that you need to activate a pillar again once you teleport back, because it resets. Also, once you talk to the pillar, it's not possible to talk to another one unless you die, so mind the spots you choose.
There are two pillars I myself suggest. The first one would be B5 (the one closest to enemy base), but the problem is it's on the B path, and we usually use C, so you'll have to fly there just once to activate it (later it's easy to activate cause you tele near it). The second one would be the pillars at C7 (near attacking base). This one is easily accessed because we use the C path, but it's not as close to enemy base as B5.
Another thing I'd like to point out is that you shouldn't teleport if you don't have full MP/HP (and preferably buffs and company) because the defending faction sometimes places a member near the teleport to kill attackers who use it.
Last, but not least, teleporters can be destroyed. If we are in the defending position, the B teleporter close to our base should be killed because their attacks will be delayed this way. Once the pillar is destroyed it doesn't respawn.
That about covers it. I hope that this short guide helps.