Subject: Guide on friendly matches....

1) how do i accept a friendly match which shows only in notification (this is after the ads published)?
2) what benefits i get in friendly?

1) Click on office and then friendlies. It will show you the active invitations.
Every time someone sends a friendly request, it will show as a notification. However, if they withdraw the request or accept a match with someone else, you won't see it on the friendlies page but it will still be there in your notifications.
It's better if you invite about 10 to 15 clubs. Someone will definitely accept.

2)You get a little cash plus your players get some more training.

Is there a forum thread for India where we can ask for friendlies?

There is; but you are better of posting & checking the Sokker International threads under 'Friendlies'.

What works for me, is that i go to the 'ads' section and send invite to 15-20 teams. Someone always accepts. :)

Yes Hexogen is right.
There are hardly any Indian managers. So it's best to follow his advice.
I normally just invite 5 teams from the top league in different countries. That's normally enough for me.