Vyas, when you 'Add suggested case', a topic is automatically created in underlying taxonomy. You can then provide matching keywords on 'Text analysis' tab or 'Edit topics' dialog. For machine learning base models, you can add records in Training data tab and assign corresponding topic to that record and build models. You can add and train custom entities on 'Training data' tab itself.
If you can elaborate on the problems you are facing, I will be able to help more.