The LHC experiments have released more than 5 Petabytes of Open Data via CERN's Open Data Portal. If you are not (yet) a researcher but want to play around with the data to learn or teach, there are several resources available.

The ATLAS collaboration has its own portal designed to get you started with exploring their data.

The CMS collaboration has published a guide to how to get started playing around with their data. If you are already more advanced, they also have a guide for how to get started with using them for research.

If you have any specific question on how to use the Portal, you can always ask your question in the User Forum or reach out directly to the open data team via opendata-support@cern.ch.

In the wider context of the high energy physics (HEP) community, the International Particle Physics Outreach Group (IPPOG) provides the following resources which make use of Open Data, not only from the LHC experiments, but also other particle physics experiments:

One way would be International Masterclasses. These are local events organized by institutions all over the world where you get hands-on experience in working with data from the LHC experiments. You find more information here: https://ippog.org/imc-international-masterclasses. There might also be an event near your home.

The IPPOG also collects other hands on open data projects such as on Cosmic Rays from the Pierre Auger observatory.