What do I need to have the same Quickbooks Desktop on three computers.

@CFM Motorsports 

You may setup a wireless LAN at your premise. If one of the user is using a PC, you may assign it as the host. You don't need to prepare a dedicated server.  But if all of your users are using a notebook and you don't need to self manage a dedicated server, consider a QB cloud hosting instead.

http://www.apps4rent.com/#a_aid=quickbooks

Thank you so much! 

Any tips on creating a wireless LAN? I thought I had it set up correctly but it isn't working. Avast Antivirus was blocking it, so I tried doing the exceptions to allow QB it still didn't work so I uninstalled and now I can't connect to the host computer. 

I can help in setting up a multi-user network for QuickBooks Desktop, @CFM Motorsports. 

Make sure QuickBooks has general permissions, so it's not blocked with Avast Antivirus. You can check with them on how to set up these permissions. Here's more information: Set up firewall and security settings for QuickBooks Desktop. 

I'd also suggest downloading the QuickBooks File Doctor. It will let you open your ports automatically. It'll also help in resolving company file issues in QuickBooks Desktop. See this article for more information: Fix company file and network issues with QuickBooks File Doctor. 

When setting up a multi-user network for QuickBooks Desktop, you'll have to set folder permissions, install Database Server Manager, set admin rights, use Database Server Manager, and turn on hosting. 

I'm always here if you have additional concerns in setting up your computers on your network. Take care and have a great rest of the day!