How do i ask donations from people for my charity?

so i was wondering i have this idea were i can stand by the grocery stores and spread atable and ask for donations when people will donate like 5 box or something they will get a free t-shirt and a packet of information about my group but i havea question do i kneed to be able to be connected with another organization with that in order for me to have the right to do that and so that it would be legal and i could proove to them that the money doesnt goes to me that it goes to my group so that i can actually get it together and have a website for it and a building and so that people who can help me with the group and spread the word bout it more like go to the mall and spread out brochures papers etc and stuff but i just kneed to know if its k to do it with permission only from the store manager or the township i don't know how to do it sorry please can u give me an advice thanx. hope u can help