Something along these lines:
nObjects = 100 // 100 objects
nCoords = 3 // 3 coordinates - x, y, z
DIM Object(nObjects, nCoords) // Dimension an array
//ETC
FOR i = 1 TO nObjects
WRITE FLOAT 1, Object(i, 1) // Object's x-pos
WRITE FLOAT 1, Object(i, 2) // Object's y-pos
WRITE FLOAT 1, Object(i, 3) // Object's z-pos
// for each object.
NEXT i
In this example we used a two-dimensional array. It's a little like those rows and columns on an excel spreadsheet. So you have three columns; x, y, z. You have as many rows as you have number of objects. I could've nested another FOR-loop inside this one, but for three statements, it wasn't worth it.
