This lego nails is not practical, it is just for fun . But if you really want to wear this, maybe you can use nail glue to stick the glitter to make it last , i only used top coat to stick the round glitters together so it doesn't stick well enough to wear . Here is the macro shot to see this mani clearly .

For this mani, i used only nail polish, you can choose any colour you want to create this, oh maybe the purple and pink lego will be cool too ! and also i didn't use any top coat on this, i wanted it to look semi-matte like how lego blocks look, so i only use nail polish for the base as well as the 4 bumps . just take your time to colour the bumps and remember to clean the small brush each time you want to get more polish so you don't have clumpy bits on your nails . 

in term of how many pieces of glitters to get the 3d look, i counted and i ended up using 6 pieces of round glitter for each stack but its totally up to you to create shorter or higher bump . and finally here is my attempt on making the video tutorial. hopefully you find it helpful :)