Load balancing SharePoint Office Web apps server

I have a farm with 2 front end servers and two application servers and 2 servers for office web apps. I am planning to use NLB services to load balance the 2 front end services.

I need to install 2 office web apps servers which are load balanced.

This article suggests installing ARR do I need to install Office web apps on both servers

and then install ARR to load balance the Office web apps servers

Would this have an effect if I had NLB services installed.

Do I need to install certificates ? While installing Office web apps are there any other prerequisite's other than a) Not Installing SharePoint

b)Running the following Powershell command

Add-WindowsFeature Web-Server,Web-WebServer,Web-Common-Http,Web-Static-Content,Web-App-Dev,Web-Asp-

Net,Web-Net-Ext,Web-ISAPI-Ext,Web-ISAPI-Filter,Web-Includes,Web-Security,Web-Windows-Auth,Web-

Filtering,Web-Stat-Compression,Web-Dyn-Compression,Web-Mgmt-Console,Ink-Handwriting,IH-Ink-Support,NET-

Framework-Features,NET-Framework-Core,NET-HTTP-Activation,NET-Non-HTTP-Activ,NET-WCF-HTTP-Activation45

c) Installing Office web apps d) POwershell command

New-OfficeWebAppsFarm -InternalUrl "https://ositeoso.com" –EditingEnabled

d) New-SPWOPIBinding -ServerName wacserver.domain-dev.com Get-SPWOPIZone Set-SPWOPIZone –zone "external-https"