by Topywo » Mon Feb 11, 2013 10:10
Press the F5 key once.
Left top of the minetest screen, under the word Minetest 0.4.4-d1, you now see something like this:
(-809, 17,5, 58,7)
0,0,0 is the center of the world
Those are your coordinates.
-809 = left/west from the center (+809 would be right/east from the center)
17,5 = above the 0-level (above the ground/in the air) (-17,5 = under the 0-level (underground, in the water)
357 = forward/north from the center (-357 would be backwards/south from the center)
For now try to go to 0,0,0 using the changes in those coordinates. Then start making circles around it bigger and bigger. You'll might find your castle somewhere in the area. Unless you really wandered off very far.
Good luck and welcome to minetest :-)