A primary beneficiary and contingent beneficiary are an important step for your estate. If your beneficiary is under 18, make sure to consult an attorney. You may need a guardian or trust set up for minors to receive the proceeds as you wish.
If you can go online to the provider website and find the correct place to enter your information, this is good. It may take a little searching, but if it is available, you will find it.
If not, your plan administrator should be a resource. Make an appointment with the plan administrator to fill out the beneficiary forms and get a tutorial about the website for your plan.
While with the administrator, you should go over your asset allocation to make sure your risk tolerances are in sync with your goals and objectives. And maximize your contributions to receive the full company match, if offered.