If you want to set up correctly the optical sync so your base stations can work properly you will find all the information you need in this tutorial. These are the required steps so you can successfully finish this process.
Step 1. So you can see if your base stations need a firmware update check SteamVR
Step 2. Make sure that your base stations can see each other and nothing can cause distraction.
Step 3. Place your base stations no further than 5m or 16ft apart
Step 4. Press the mode buttons that are placed on the back of your base stations so you can adjust the on base station “b” and the other base station “c”
Step 5. If you have done everything correctly the light of the base station should turn to solid green.