The Lisbon strategy is basically a plan that was made by European countries over 20 years ago to try and make Europe a better, more successful place. Think of it like a family deciding to make a plan to have a better life.
The plan had different goals, like making sure people had more jobs to apply for, improving education, and helping businesses grow. The idea was that if all these different things improved, the countries in Europe would be better off in the long run.
It's kind of like if a school wanted to make sure all the students were doing well, they might make a plan to improve the playground, offer better lunch options, and add more after-school programs. All those things might help the students feel happier and more successful.
The Lisbon strategy was a big effort by Europe to try and make things better for everyone living and working there. It might not have solved everything, but it was a really important step towards a better future.