Installing OWA on a Server 2012 Box
Save yourself some time and download the install bits and the KB Update bits before you start.
KB can be downloaded here…
http://support.microsoft.com/kb/2810007
Also, go ahead and download the language packs. They can be downloaded here…
http://www.microsoft.com/en-us/download/details.aspx?id=35490
The powershell step below can be run at the same time, and depending on your download speeds you can go grad some coffee or lunch. Obviously, you will want to let the downloads complete before you restart
Note – this cannot be installed on a SharePoint box, it needs to be on a separate box.
First thing is first run this powershell command. It’ll install the prereqs. You need to be an administrator on the box and you are installing on. Make sure to run the powershell console as an administrator, copy the command below exactly and right click in the powershell cnosole window.
Add-WindowsFeature Web-Server,Web-Mgmt-Tools,Web-Mgmt-Console,Web-WebServer,Web-Common-Http,Web-Default-Doc,Web-Static-Content,Web-Performance,Web-Stat-Compression,Web-Dyn-Compression,Web-Security,Web-Filtering,Web-Windows-Auth,Web-App-Dev,Web-Net-Ext45,Web-Asp-Net45,Web-ISAPI-Ext,Web-ISAPI-Filter,Web-Includes,InkandHandwritingServices,NET-Framework-Features,NET-Framework-Core

You should receive this message…

Restart your server.
Download the install bits, and start the install.

Double click set up to start the install

Accept the license and click continue

Choose a file location and click install now.

Which will bring up this screen

Once the installation is complete you’ll receive a message indicating its completion.
Next you’ll need to install the KB updates located here…
http://support.microsoft.com/kb/2810007
Download this to your server. You may receive an error that says you can’t download the file. Depending on your server standards and rights you can change that setting in IE to allow downloads via these instructions
http://www.globalnet-iti.com/innovations/blog/how-to-resolve-your-current-security-settings-do-not-allow-this-file-to-be-downloaded-on-a-server/
I really only needed to go down 7 bullet points before it worked. I’ll likely set it back when I’m done.
Open the download and you’ll be presented with an install screen…
The update will take a few minutes to install after which point you will receive a message that indicates it is complete.
Just cause you always should after a KB upgrade, you want to restart the server.
Next you need to install the appropriate language pack, which you should have downloaded when you started. If you didn’t it can be downloaded here..
http://www.microsoft.com/en-us/download/details.aspx?id=35490
Run the download

Accept the teams and click continue.
When it is finished you’ll see this…

Click close and prepare to configure.
I’m going the https route so the powershell I need to run is as follows
New-OfficeWebAppsFarm -InternalUrl https://internalurl.com” -ExternalUrl https://externalurl.com -CertificateName yourcertname -EditingEnabled
You’ll be asked if you are sure you want to enable editing, in my case I do, so I said Y. After that I was presented with all the OWA farm settings in the powershell window
Now to check if the farm is properly configured…
Put the internal URL in a web browser like so
https://internalurl.com/hosting/discovery
If you are presented with a fairly large xml file. This file is the Web Application Open Platform Interface Protocol (WOPI) XML file and have a similar beginning portion to the xml below.
<action
name="view"
urlsrc="https://wac.contoso.com/x/_layouts/xlviewerinternal.aspx?”
default=”true” ext=”ods”/><action name="view"
urlsrc="https://wac.contoso.com/x/_layouts/xlviewerinternal.aspx?”
default=”true” ext=”xls”/>>> all programs >>> microsoft sharepoint 2013 products.
Create a binding between SharePoint 2013 and OWA
New-SPWOPIBinding -ServerName

After running this command you’ll see a result that lists what all types of files it handles etc. Just take this as a success message and move on.
To see which zone OWA uses to communicate with the host run the following command
Get-SPWOPIZone
It defaults to the internal zone, which depending on your configuration may not work. For instance, if you have a farm that is both external and internal you want to set this to external which you can do by running the following command
Set-SPWOPIZone –zone “external-https”
Now verify that OWA is working…
If you click on an office document and it opens in the browser you are good to go. If it doesn’t open, you are set for external-https or external-http, and you get a page can’t be displayed error, you may just need to wait for the Public DNS to refresh. It took a couple hours for me, so it may require some patients. If the portal you are working on is live go ahead and run this command to remove it until you are able to type in your external URL and you get the same results as you did for your internal.
Remove-SPWOPIBinding –All:$true