Real basic:
Settings > All Settings
Expand Deployment and Migration
Expand Symantec Boot Services (PXE)
Remember to always save changes.
Add preboot configurations for WinPE or Linux, depending on what you want
For example you might create one called MyCompanyWinPE which has x86 architecture WinPE for both PXE and automation
Choose sysprep configuration files and upload Deploy.cab, which you can find on a Windows CD or online -- used by the Prepare for image capture task
Start the PXE services on your NS
Add OS Files and OS Licenses. OS Files are not necessary if you aren't doing scripted installs yet. OS license is necessary because sysprep will request it later.
Jump up to Agents/Plug-ins > Deployment and Migration > Windows (x86) or (x64)
Enable automation folder and plug-in for your computers
Create three new tasks, and then a job to contain them. This is all done under Manage > Jobs and Tasks
Prepare for Image capture
Gather image
Reboot to production
Your prepare for Image job should specify whether you reboot to Automation (a local WinPE copy stored on the hard drive of the client machine, if you've enabled it as recommended above) or PXE (load over network and then boot to temporary WinPE).
Your create image job should be 'Disk image' if you're using Prepare for Image capture. If you want to skip Prepare for Image capture, you can make this a Backup Image. Sysprep is not required, and the image will not be replicated. Instead, it stays on the NS or site server that gathered it. This is a nice option while you work out network issues, driver issues, and anything like that. You're just backing up the system then later creating a job to deploy it right back to the same system. No reason to fuss with sysprep yet.
Third, create a Reboot To task that Reboots to production.
Finally, create a job encompassing these two or three tasks, then apply it to your test system.
This was quick and dirty, hopefully I didn't miss anything.