Is it true that we must name our Kumantongs? How to go about doing it?

"Is it true that we must name the Kumantong because I think my Kumantongs does not have a name... if yes... what is the procedure?"

It is good to give each of  Your Kumantongs a name.
Name can be "小胖" (Fatty) , "小黑" (Blacky),"Zai Zai" and any cute names You can think of. If You have many Kumantongs, make sure You record down and remember the name You have given to each of them.

"What will be the procedure or rituals to perform for naming the Kumantongs?" 

Always burn Incense Cones / Incense Sticks or Kominyan, when performing naming ceremony.

1) Bring out the Kumantong and hold it on Your hand.
2) Do any Kumantong Chant that You know of.

One Universal Kumantong Chant You can use:
Namotasa Bagawato Ahrahato Samma Samputasa (x3)
Kumalomama Aihicitang Piyangmama (x3)

3) After that, say to the Kumantong:
Example - " Kumantong, now I will be giving You a name.. and the name is "小黑" (Blacky). From Now on I will call You "小黑" (Blacky)."

When You want to ask Your Kumantong for  Lottery Numbers in future, You can call by the name "小黑 (Blacky),  Please come out now. i want to ask 4D Number.. Please give me 4D number for today".

You can speak the language,that You often speak, to Your Kumantongs. They listen and feel from Your heart.