You do not need to fill out the bottom part of the affidavit as this must be done by the commissioner or notary. Only the top part and the statements listed in numbered paragraphs inside the large box need to be completed by you. The commissioner will ask you to verify your statements.
You can have an affidavit sworn for free by a commissioner of oaths on staff at the Landlord and Tenant Board. To have one sworn in advance of going to the Board, you would likely have to use a lawyer, paralegal or notary public at your own cost.
Instead of an affidavit, the LTB will also accept a signed and dated declaration containing the same information. The person who makes the declaration must confirm the truth of the information or statement and acknowledge that making a false declaration is an offense. Declaration forms are available on the LTB’s website-https://tribunalsontario.ca/ltb/forms/