This is an opportunity you cannot afford to miss. Retirement can last 25 - 30 years. You need a good nest egg to make that wonderful time of life comfortable. Contributing even a small amount each month can add up to a sizable nest egg over time through the power of time and compounding. Understand you investment choices and study your options carefully.
Mutual funds are the most common choices.
Be sure you are investing in the right asset class for your risk tolerance, age and time horizon. Investing too conservatively for a younger person is a common mistake. There are many information sources available to educate yourself on the types of funds you should be choosing for your particular situation. Unfortunately, the plan doesn't usually give you that information. You have to do your own research.