In this Multi Part Article, I going to show you how to setup SQL AlwaysOn whish is very much supported for Skype For Business.
SQL Installation
Select New SQL Server Stand-alone and click Next
Since I am installing in Test lab, I going with the Evaluation Version
Select Database Engine Services and management Tools-Basic, Management Tools-Complete
Set Startup Type Automatic and Click Next
Select the Administrator Account and Click Next
Open SQL Server Configuration Manager and Click on SQL Server Properties
Select Enable AlwaysOn Availability Groups and Click Apply

Restart the SQL Service once AlwaysOn is applied.

Open SQL Management console

Click Connect

Right Click on databases and Click on New Database to a Test Database

Here is the Test Database with Database Name: SFB-ON

Follow the above steps and install SQL in Second Server as well.
Right Click on AlwaysOn High Availability and Select New Availability Group Wizard

Click Next

SKYPE-AON is the name and Click Next

You would get Full Back is required Alert if you have not taken the back

Here I have not taken the Backup here before hence processing the Backup by right Clicking on Test Database which we created and click on backup

Click OK to Backup

Once Backup is completed, Click on Refresh

Now you will see the Status is Meets prerequisites, Click Next

Add Replica Servers

Select Automatic Failover and Synchronous Commit and click Next

Without fail add the Listener Name: SFBAON-Listner and IP address for it and Click Next

Select the File share which we have created during the Cluster Creation

You can see the Second server added and database also synchronized.