One of the top concerns for seniors who work after retirement is how additional income will affect their social security benefits. The best way to know for sure is to meet with a financial advisor. However, you can start the learning process online. Having a basic knowledge will help you know what questions to ask. You can start here:

How Work Affects Your Benefits
Will I Get Penalized for Working While Collecting Social Security Retirement?
How Are Social Security Benefits Affected By Your Income?