How To Aerate Your Lawn
There are many types of aerators. Lawn aerator footwear allows you to attach tine-bottomed shoes on your feet and then stomp around in your yard. You can use your body weight to penetrate into the soil. Tow-behind Aerators can be pulled behind your mower. Gas-powered aerators let you walk behind them, just like a push mower
How to begin
Before you begin you might want to take a look at How to Give your Lawn a Boost.
You should water your lawn well 24-48 hours before you plan on aerating your yard. This will make it easier for the aerator and core pullers to penetrate the soil. Flag any obstructions in your yard which could cause damage or may be detrimental to the aerator.
If you have very compacted soil or soil which has not been aerated in the past year, it is a good idea to do two passes with your aerator. The first pass should be done following your mowing plan. The second pass should be made at an angle. One pass is sufficient to aerate soil every year.
When your done
When you have finished aerating your lawn, you can apply fertilizer to your lawn or seed it if needed. These holes allow fertilizer to reach the root system more easily, which allows access to the root system, allowing fertilizer to work more effectively.
As for the leftover cores, you have two options: leave the soil cores alone to naturally decompose or break them up with a light raking.