How can we give names to the organic compounds by IUPAC method ?

First count the number of carbon atoms forming the longest continuos chain and give the root word.

C1---meth, C2---eth, C3---prop,   C4----but,  C5---pent, C6----hex, C7---hept, C8----oct, C9----non, C10---dec,

See cabon to carbon bonds and pri suffix it to root word. Than see if there is a functional group suffix it to ane, ene and yne by removing e. Any other atom or goup of atom left will be prefixed.

For single bonds suffix ane, for double bond write ene and for triple bond write yne. If the number of double bonds is 2 than add diene and so on.

alkyl, halo, nitro to be prefixed root word + pri suffix - e + sec suffix