The ozone layer is very difficult to repair because it is an accumulation of gases in the sky -- it's not something we can physically touch to repair. Some materials that were used in refrigerators and aerosols caused big damage to the ozone layer before scientists realized what was happening. On the bright side, once scientists discovered what was happening it was internationally agreed to stop using these the damaging materials and the ozone layer stopped getting worse.

Big masses like the ozone layer change over such long time scales that it could be another 50 years before it is recovered, but we use satellites to track it's progress and it has definitely been improving.

So the big plan to help it recover is to stop using the materials that were hurting it and let it recover, and so far it has been effective.

This is a great question. The short answer is that scientists and engineers have been working successfully to reduce ozone damage for decades!

Ozone is important, because it blocks most of the Sun's ultraviolet (UV) light from reaching us (UV light is what gives us sunburns, skin cancer, and damages our eyes). The problem is that when chemicals that we make containing chlorine get into ozone layer of the atmosphere, they break down ozone molecules. Fortunately, we recognized that this was a problem in the 1970's, and countries (including the USA) started to ban the use of the chemicals that were causing the most damage. Then in 1987, 197 countries from around the world signed the Montreal Protocol, which set out a formal plan to reduce the production and use even more chemicals that react with ozone.

Although there are still many human-made chlorine-containing substances that reach the ozone layer, this international collaboration has greatly slowed down the damage to the ozone.

We are fortunate that the Earth's ozone repairs itself naturally, so the best and fastest way to repair the ozone is to find/invent new chemicals that can replace the harmful chlorine-bearing ones, and this is exactly what we have been/still are doing. The challenge is that the new chemicals need to be affordable, because the harmful ones are used in many important things that we need in modern society:
fire-extinguishers, refrigeration, solvents, propellants (high-pressure gases used in spray cans), and more.

The plan is already in motion and has been for some decades. Basically it consists of getting unnatural halogens (mainly chlorine) out of the air. Since we don't use freon anymore, this is happening through natural processes, and the ozone layer is recovering.