Hello Santosh,
There are around 25 trainings which are currently available in the Ariba through the SAP training and certification shop. Out of these some of them which are relevant for Contract include AR210, AR220 and AR230 and ones for sourcing include AR110, AR120, AR121 and AR130 and ones related to administration include AR720.
One other training which could be of some interest from the Ariba point of view is the one related to Supplier Information and Performance Management (AR310 and AR320).
These are all the ones which are primarily related to the upstream modules and since some of them overlap with the others in the same stream choose wisely on the ones you are really interested and would give you knowledge to work on in Ariba.
I don't think there are any classroom trainings for Ariba and they are all virtual classrooms. Also there is something known as the Learning HUB which will give you access to many courses as e-learning module.
Check the link below which lists all the Ariba courses and also the contents for each of the courses. This will help you to plan better on how you would like to take this forward.
https://training.sap.com/shop/sap-search?q=*&refine%5Bsolution%5D%5BCloud%5D%3DCloud
Regards
Pramod