The first animations you see as soon as you have assembled the clock are an example. They are so colorful and vivid because that example is supposed to show you what the clock can do. In the software there are more files you can apply to the clock to change its look.
Additionally, with these animations you can check immediately whether the clock was assembled correctly and whether all of its parts work properly.
Please read the section “Customizing the LED-Nixie Clock” to find out how exactly you can change the settings of the clock.