Warps are preset areas that you can teleport to using the /warp command. To use a warp you simply type in /warp warpname. Warps are case sensitive and can have spaces in them. This means that /warp my house is not the same as /warp My House or /warp MYHOUSE.
Warp names should be something easily remembered. There are several places that have warps listed including the room at the end of the rules in Mainland (/warp Rules); the Notice Board in the library (/warp TheLibrary) and the Welcome Center in Peaceful (/warp wc).
As ships begin to travel around the worlds, there will be warps listed in the hold of each ship that point to previous spawn points for that world.