I created an empty 12*12*12 cm cubic part with a 3*3 cm square inside and depth of 0.75 cm. then I made another part which is a 3*3*1.25 cm cube to insert inside that 3*3*0.75 space. I need this part to be adjustable but I'm not sure If I did it correctly while mating the two parts. Does the commands look correct? If not what should I do?