Let's imagine you have a big box of crayons, each with a different color. You want to use some of these colors to create a picture, but some of the colors you need are scattered throughout the box. So what do you do? You use a pair of scissors, carefully cut out each color you need, and then glue them together to make your picture.
This is similar to how the "paste" command works in Unix. In Unix, you can use different commands to manipulate text. "Cut" lets you remove pieces of text, and "copy" lets you copy them to a new location. But what if you just want to take all the pieces of text you've cut or copied, and stick them together in one place? That's where "paste" comes in.
For example, let's say you have a list of names in one file, and a list of corresponding ages in another file. If you want to put them together in one file, you could use the "paste" command. It would take the first name from the first file, and the first age from the second file, and put them together in a new file. Then it would do the same for the second name and age, and so on, until you have all the names and ages in one file.
Basically, the "paste" command lets you take different pieces of text and stick them together. It's like using scissors and glue to make a picture out of different colored pieces of paper!