Office Online Server is the successor to Office Web Apps Server. It may be connected to SharePoint, Exchange, Skype for Business and many other applications to display, create, edit Microsoft Office documents. The following procedure will guide you through the installation process to deploy Office Online Server with SharePoint Server 2016.

Execute the following PowerShell command with administrative privileges to install the required Windows Features on your Office Online Server(s):

Install these software packages on your Office Online Server(s):
.NET Framework 4.5.2
Visual C++ Redistributable Packages for Visual Studio 2013
Visual C++ Redistributable for Visual Studio 2015
Microsoft.IdentityModel.Extention.dll

Download the Office Online Server software from your Microsoft software portal and run the installer using an administrative account on your Office Online Server(s). You you need to install any language packs, you may download them here: http://go.microsoft.com/fwlink/p/?LinkId=798136.

Restart the Office Online Server(s).

Create a DNS A-record for oos.yourdomain.com and point it to the Office Online Server or the Load Balancer if you have more than one Office Online Servers.

Create a SSL certificate which contains an entry for oos.yourdomain.com. You may also use a wildcard certificate for yourdomain.com. Add this certificate to the certificate store of your Office Online Server(s) – just double click and choose to install it for the machine.

Modify and execute the following PowerShell commands on one of your Office Online Server(s).

Add the parameter -externalURL to define a different URL for accessing your Office Online Server farm. Shouldn’t be needed in most cases because you’re already using a FQDN with your internal URL. The parameter –CertificateName reflects the friendly name of your certificate.

Open https://oos.yourdomain.com/hosting/discovery in your browser. Proceed if you see a XML page.

Move over to one of your SharePoint servers, open the SharePoint Management Shell and execute the following commands:

Optional: Reboot your servers (I think it might help…).

Navigate to a SharePoint site using a non-admin user (don’t use the install or farm user) and try to create a new document. It works? You’re all set. If you have trouble make sure you rebooted the servers and re-check the steps above.

To join additional Office Online Servers to the Office Online Server farm execute the following PowerShell command on the Office Online you want to add:

Server1.yourdomain.com reflects the name of a Office Online Server that is already in the farm.

More information on TechNet: https://technet.microsoft.com/en-us/library/jj219455(v=office.16).aspx