Here's a snippet that puts a label at the provided position. No time or billboard involved. I grabbed this from our simple.czml example in Apps/CesiumViewer/Gallery/
{
"id":"/Application/STK/Scenario/simple/Facility/AGI",
"label":{
"fillColor":{
"rgba":[
0,255,255,255
]
},
"font":"10pt Lucida Console",
"horizontalOrigin":"LEFT",
"outlineColor":{
"rgba":[
0,0,0,255
]
},
"pixelOffset":{
"cartesian2":[
12.0,0.0
]
},
"scale":1.0,
"show":true,
"style":"FILL",
"text":"AGI",
"verticalOrigin":"CENTER"
},
"position":{
"cartesian":[
1216469.9357990976,-4736121.71856379,4081386.8856866374
]
}
}
I hope that helps.
Matt