Don't Manually Install If You Feel Uncomfortable
If you don't want to wait for your Galaxy S8 Oreo update you can manually install the software right now provided you have the right device and the right skills for the job.
Now that the official Galaxy S8 Oreo firmware is out, select Galaxy S8 users can skip the OTA (Over-the-Air) roll out and install Oreo right now.
If you're feeling impatient you might be tempted to install Oreo right now. However, if you feel uncomfortable with any part of the process you should wait for your OTA to arrive.
Manually installing Android software upgrades can be more trouble than it's worth so make sure you feel confident before you begin.
Most Galaxy S8 Oreo updates should roll out in the first half of the year so don't force it. If you do, you might wind up with an unnecessary headache.