All you need to do is create a job to download all your configs. I have one that downloads all my startup configs once a week. Then an hour later on the same day I also download all the running configs and in that job I compare my running config to the lasted config downloaded so that I can check if others are "writting" off the configs.
And I use realtime change detection to keep the configs up to date as changes are made.
Alternatively if you have NCM version 7.3.2 or lower, you can use the GUI on the Solarwinds server. Just click on Nodes and select Download Configs. Then just add in the devices you want to get the configs from.
Hope that helps.