Hi
@UshaSree Lingam,
Have you worked through the demo labs that are provided for free on the DX? Those will give you a pretty solid understanding of the foundations within Blue Prism. I'd start there first. You can work through them all in a day if you put your mind to it.
After that, you need to decide how you want to integrate with Ariba. There are two options: UI automation or API. I generally recommend taking the API approach to integrating with a platform if an API is available. Ariba offers several APIs. In fact, there's at least one Ariba integration available in the DX now.
Cheers,