Connection of the lower end of the kitchen sink drain to the drain pipe

Under my kitchen sink, at the connection point between the sink drain and the drain pipe, the drain pipe has come loose. I see a rubber gasket that is placed between the end of the drain and the pipe. I don't know how the drain pipe came loose. Can I, as a layperson, reconnect this drain pipe myself? If yes, how? (please no technical jargon, as I am a layperson). The drain pipe is made of plastic.