Rez it on the ground and the particle effect will start.
Type "/66change" and a menu will drop down allowing you to choose 20 star textures, 117 colors, 3 sizes, 3 radii or turn the particles on/off.
Caution: If you choose "finalize" in dialog box then the type, color, size and radius is fixed. (even if you type "/66change", dialog box won't drop down)
You can also use voice commands on channel 66, as follows:
Texture: /66 texture UUID - UUID is the UUID of the texture you want to use. To obtain that key, find the texture you want to use in your inventory, right click it, and choose 'Copy Asset UUID', and then ctrl+v, it'll get you the desired key. The command will look like this: '/66 texture c6dbc4b2-918c-b224-8f8d-210b9a07fabf'
Size: /66 size VALUE - changes the size of the particles, range 0.03125 - 4.0. (default size is small - 0.5, normal - 1.0, big - 2.0) The command will look like this: '/66 size 1.0'
Radius: /66 radii VALUE - changes the distance from center of the particle emitter. (default radius is narrow - 8.0, middle - 12.0, wide - 18.0) The command will look like this: '/66 radii 12.0'
Count: /66 count VALUE - changes the number of particles released every burst. The command will look like this: '/66 count 30.0'
Time duration: /66 age VALUE - changes the time duration of the particles, range 0.1 - 30.0. The command will look like this: '/66 age 2.0'