>>399442Okay, dude. No problem.
You look up when they have the next soup kitchen event. If they provide a time interval, e.g. soup kitchen is open between 2pm and 4pm you go there 10 minutes before they close (to avoid the line, and to not disturb them while they are working) and approach them.
You should be friendly and direct. A "hi guys" or whatever the fuck is the informal equivalent is in your language will do. If they offer, you tell them that you are not there to receive food, you'd rather see it go to people who need it. You then tell them that you have been following them online [twitter, facebook, youtube, wherever] and you really like what they are doing.
You tell them that you would really like to help out however you can. If you have cooking experience you should tell them. If you can help with basic food preparation (chopping vegetables, etc.) you should offer. If you could help them set up the tables and chairs every event, the same. But make sure to listen to what they tell you they actually need.