If I exercise NUA on my company stock and transfer the shares to a brokerage acct., questions on taxes

1) If I sell a portion of the shares, I will receive a 1099-B for those shares, I will report the gains on stock sales; correct
2) On my 1099-R the Gross Distribution nad NUA is reporting the total for all of those shares; my question is if the capital gains must be paid on the shares that are transferred now or when they are sold at a later date