Frictional unemployment is when people who are looking for jobs can't find them right away.
Think of it like this: Imagine you want to buy a toy, but you can’t find it at the first store you visit, so you have to go to another store. While you are on your way to the second store, you are technically "unemployed" because you don't have the toy yet, even though you are actively looking for it.
Similarly, people who are searching for a job may not find the right one immediately, so they remain unemployed for a little while despite actively searching for work.
This type of unemployment can be frustrating, but it is a normal part of the job market. Sometimes it takes time for employers and job seekers to find each other and match up. It's important to keep trying, keep looking and keep applying until you find the right job for you.