Have you posted in this thread?
Welcome to the community! 
Post this in this thread:
I know Telegu and Tamil subbers but I’m not sure about Malayalam. Maybe @padmalayag can help you find Malayalam subbing volunteers (she’s a Telegu subber) 
It would be nice if you had a senior to help you get to know the Malayalam subbing rules and other things.
It’s not mandatory to have experience in subbing. I’m glad you watched the subtitling tutorial so you know what everything looks like. If you have any questions about how things work, feel free to PM me (click on my username and then click the blue “Message” button on the popup that is displayed).
I hope you have a wonderful time volunteering! 