Shielding and unshielding with Tezos works by switching between two versions of the Tezos blockchain - the "normal" Tezos and Sapling Tezos. Shielding is the process of converting your normal Tezos tokens into Sapling Tezos tokens, which are shielded from public view and provide enhanced privacy and security. Unshielding is the process of converting your Sapling Tezos tokens back into normal Tezos tokens, which are visible on the public blockchain. Both shielding and unshielding require a valid Tezos account and the use of a Tezos wallet. Shielding and unshielding can be done through a variety of methods, such as using the Tezos CLI, a web-based wallet, or a mobile wallet. The process is relatively simple and straightforward, but it is important to understand the security implications of shielding and unshielding your Tezos tokens.