Need basic help: How to upload my own map?

[Bravestarr]

If for some reason /setspawn doesn't work, you can always edit the player data file - in the "players" folder there's a bunch of subfolders and in each a bunch of .json files, each corresponding to one player (based on their UUID); open them in notepad and change the SpawnX, SpawnY, SpawnZ coords in there. There's also a "lastknownname" somewhere in that file, specifying the player name, to help you locate the correct file.

It did not work with /setspawn but it worked with the players json file. Is there a way to change this for all new players? 

 

And I am still unable to enter the Nether. I tried to edit the world.ini like this (cubrite is not running):

[LinkedWorlds]
NetherWorldName=world_nether
EndWorldName=

But after I tried to enter the Nether in the game the parameters are gone. 

the folder "world_nether" exists and there is a world.ini and region files in there. Any idea?