This is how i would explain (i suppose you mean to ask panjaban that if we are explaining it to a non-punjabi, lets say Gore)
I would first explain about Punjab that we a northern state in India, and coming from the state of punjab we are called Punjabis. In punjab hindus and sikhs make the majority of the community and eventhough belonging to 2 different religions we share the same culture. (Appa culture explain karn di gall kar rahe haan, haina? religion di ta nahi, just makin sure). Then i would explain about our traditions, pretty much from coming to this world to leaving this world and how our families are out biggest support system and our most important priority. I will explain that we have no concept of a kid moving out when he/she turns 18. Our parents provide us everything when we are growing up and when its their old age we stay with them, we dont send them to senior homes (that cud be offensive to some gores, but i will try to explain is somewhat subtle). Then i will explain that we are a very lively culture, we are very closely tied people, I will explain about the traditional and folk dances, and tell them that on every occasion of happiness, at the birth of a child, someone's marriage, celebration of someone's success, or anyother occassion we express our happiness by dancing bhangra and gidha. Bhangra is pretty much a dance out of joy performed by guys and Gidha is typical of girls. I will then explain somewhat about the traditional food, which is pretty common these days even in Gore people. Food is a big part of our culture and we eat well cooked food ...lol...We eat things like daals (lentils), saag, cheese (paneer), some people do eat meat and bread which could be roti or naan and rice. Another thing i will emphasize is that cheese, milk and yogurt are a big part of a punjabi's upbringing (or atleast was mine...lol). Then i will explain about our dressing style, how a suit looks, I can tell them that a kameez is a long shirt worn with a shalwaar which is somewhat baggy pants and also a dupatta/chunni which is a veil, And thats worn by women. And men these days normally wear pants and shirts, but traditionally they wore Kurta-Pajamas which are again long shirt worn with pajama kinda pants. I can tell a little bit about the jewellery we wear, which is normally made out of gold (although i hate it, but our women love to).
And then i can also explain that religion is a big part of our culture is too, be us HIndus or Sikhs and most of the times thats the reason for our fights, lol.....well just joking.
I guess superficially thats enough for someone to know, but yeah there can be more detail to it deeply, But as u asked only for someone who knows nothing about us, i think this will be atleast something.