I'll give you some examples, hopefully this helps:
NPC Code:
with (findnpc("NPC Name"))
with (allplayers[i])
NPC Code:
for (item: clientr.item)
for (i=0; i<allplayerscount; i++)
NPC Code:
setlevel2(level,x,y);
player.setlevel2(level,x,y);
I believe these are all the player-level manipulations you can do:
player.level - object, read only
player.x - floating point value
player.y - floating point value
player.z - floating point value