You should always add transaction like they took place. This is the case for all trades and gains.

As an example:

- OUT "General Withdrawal" of the given capital from a wallet / exchange to the POS pool

- IN "General Deposit" into the POS pool. You could name the exchange field "POS pool"

- IN "Income" on the "POS pool" exchange in the amount of whatever your assets are raised by the staking rewards. This income could be put into a group called "staking" to better filter for them. This is a taxable transaction.

- OUT "General Withdrawal" from the "POS pool" exchange in the amount of the withdrawn capital that now is transferred to a different wallet or exchange.

- IN "General Deposit" in the appropriate wallet / exchange that receives the rewards.