Celsius and Voyager bankruptcy

With the ongoing Chapter 11 Bankruptcy cases with Celsius & Voyager - i see we can claim the crypto lost there as an 'investment loss'. Or a casualty loss - which is not tax deductible.

 

If we make it as an investment loss, can you let know the steps in detail as to how to mark it as loss. 

 

Please let know if my above understanding about bankrupt exchanges & investment loss is incorrect.