Office 2019 now uses click-to-run technology instead of 'setup /admin' there are a few changes, probably for the best in the long run.

Create Config Files

First you need to download to Office Deployment tool

This is a self extracting file that spits out setup.exe and 2 sample config files - one for 32-bit and one for 64-bit.
Edit the edition you want to download. If you want the Volume License version change the Product ID to 'ProPlus2019Volume'

You don't need to add Visio or Project as they are also downloaded.

Save the file and run 'setup.exe /download configuration-Office365-x64.xml'.
This will run in the background and download into a subfolder - Office.

Now you have the files you can make configurations using these resources
https://config.office.com/ - Spits out config files for Office 365 - At time of writing it isn't made for 2019 yet but should work ok.
https://docs.microsoft.com/en-gb/DeployOffice/office2019/deploy - Documentation on customising the confiuration files.

If you want a head start I've made config files for Office, Project and Visio - Download 

Example - Office 32-Bit, exclude OneDrive and Skype, accept EULA, Silent install, some customisations from Config.office.com

Test

To test your config files run setup.exe with the configure switch

setup.exe /configure configuration-OfficeProPlus-x86.xml

Deploy

Create an application in SCCM - with your files.
Deployment type - Script Installer

For Detection Methods:

Office - 32-Bit: %ProgramFiles(x86)%\Microsoft Office\root\Office16\Winword.exe
Office - 64-Bit: %ProgramFiles%\Microsoft Office\root\Office16\WINWORD.EXE

Project - 32-Bit: %programfiles(x86)%\Microsoft Office\root\Office16\WINPROJ.EXE
Project - 64-Bit: %ProgramFiles%\Microsoft Office\root\Office16\WINPROJ.EXE

Visio -  - 32-Bit: %programfiles(x86)%\Microsoft Office\root\Office16\VISIO.EXE
Project - 64-Bit: %ProgramFiles%\Microsoft Office\root\Office16\VISIO.EXE

KMS

Download the Volume license app http://www.microsoft.com/downloads/details.aspx?FamilyID=878fef7e-3f4d-4d22-a423-f447c0f5bfdd
On the KMS server run the exe.

Follow the Wizard Prompts

Get your Office 2019 KMS Key from your Key Holder

Don't Click Commit! Click Cancel as you already have this configured