Thanks for your question. The slip T5008 has Box 20 and Box 21. When you fill out both these boxes with a book value of securities and proceeds of disposition, the capital gain etc will be automatically calculated and reported on Schedule 3 of your return. Net Proceeds will go in Box 21, Book Value or the price at which you bought the shares will go in Box 20. Sometimes, the T5008 does not have Box 20. If this is the case, you would need to contact your financial institution that issued the T5008 and get the net book value or a summary of trading from them.