When you spot a record of interest, you copy the Instrument # and then obtain the full record (deed, indenture, will, etc) Many are on microfilm.
Usually there is a long description of the exact piece of land (outside boundaries), plus names of all persons involved in the transaction. There will be witnesses and a date. You may also find names of other people, such as heirs, or children --- it all depends what the transaction is. Wills are just that - wills that have been filed with the land records.
Some of the instruments I obtained in my searches of land records contained first names of wives - which had been unknown to me before finding them mentioned in the land records. So it's a valuable resource!
See http://olivetreegenealogy.com/can/ont/land.shtml for more help and explanations