I am not able to understand the shape of orbitals and the concept of hybridisation. Please explain it to me in the best possible way you can

to find hybridisation of any molecule ,ion use HON rule

according to this

                     x = (number of electron in valence shell of central atom + no of monovalent atom - charge)/2

if X = 2 , hyberdisation is SP

if X = 3 , hyberdisation is SP² & so on

eg) NH₄⁺

   X =  (5+ 4 - 1)/2 = 4  = SP³

H₂O

   X = (6+2)/2=4 = SP³

CO₂

  X=(4)/2 = 2 = SP