I know this is probably a bit vague not knowing much about it.
Can someone provide me with information or point me in the right direction on how to use Launch Agents with Jamf Pro server. For example https://github.com/grahamgilbert/macscripts/tree/master/set_desktops
An example would be to default the background wallpaper, we've got, for all users but it would be great to know about launch agents to. So I could possibly use it for other things.
To be honest, aside from the fact you might use JAMF to deploy LaunchAgents they are both each their own thing, good for different purposes for a variety of reasons.
There is plenty of information around the internet about what files need to be where to create a LaunchAgent, it's just a matter of applying it to JAMF.
Deploying LaunchAgents with JAMF is really just a case of either scripting the creation of one or capturing the required files in Composer and then deploying it.
I suppose the other thing you could use LaunchAgents for is calling JAMF policies by trigger, which just means having them call
jamf policy -event "SOMETRIGGER"
Then having a JAMF policy setup to respond to this.