You should take the I-797, a copy of the H-1B petition, and your passport to the US embassy or consulate post with jurisdiction over your home. There, you will present the information to a visa issuance officer, who will ask you to fill out a preliminary application for the visa.
Once you have acquired your H-1B visa, which will be stamped in your passport, you are eligible to request admission at a US port of entry. Be sure that you have in your possession your I-797 (which the visa issuance officer will return to you) and your passport when you travel. When you arrive in the United States, your documents will be examined and processed by a staff member of the Department of Homeland Security at the port of entry, after which your I-797 form and passport will be returned to you. These documents are extremely important since they legitimize your presence in the US, and you should keep them in a safe place. Once you are in Huntsville you should find your I-94 card number from https://i94.cbp.dhs.gov which you will need to get a social security number, AL state ID, or driver’s license.
Canadian citizens do not need visas to enter the United States. They enter by presenting the I-797 form, copy of the H-1B petition, and a valid passport at the port of entry to the United States.
You must bring your passport and visa documents to the OIE. This should be done no later than your first day/date of hire and before you apply for your social security card.