Project portfolio management is like having a toy box full of toys. You have many different toys in your toy box, but you can only play with one toy at a time. You need to choose which toy to play with depending on what you want to do and what you are feeling at the moment.
In the same way, a company has many different projects they can work on, but they can only work on a limited number of projects at the same time. Project portfolio management helps the company decide which projects to work on and when.
Think of it this way. Let's say a company is building a new playground. The company has many projects, like building a new swing set, a slide, and a climbing wall. They also have other projects, like building a new office building and creating a new website.
Project portfolio management helps the company decide which projects to work on first, which projects can wait, and which projects aren't important at all. They take into account things like how much money they have, how much time they have, and how much each project will cost.
Just like how you choose which toy to play with, the company chooses which project to work on depending on what they want to do and what they need at that moment. Sometimes this means working on a big project, like building the playground, and other times it means working on smaller projects, like fixing broken swings.
Overall, project portfolio management helps a company make good decisions about which projects to work on, so they can be successful and have fun just like you do when you play with your toys.