If you go to http://www.cic.gc.ca/english/immigrate/sponsor/spouse-apply-how.asp#step1 there are two links. Use the 2nd one where it says: If your spouse, partner or dependent child lives abroad, use the Application to Sponsor a Member of the Family Class.
You do have to get sponsored for immigration to get residency unless you choose to apply for residency on your own by using some other immigration class which will probably take longer and cause you to have to fill all kinds of requirements which may be hard for you like having a job offer etc.
You do not have to land before you get sponsored. First you get sponsored, then you land, after you get the PR visa.
Because you live abroad, you and husband will have to prove intent to live in Canada after you get PR. This could be something like a letter of job offer, acceptance to college, arranging housing, letters of support from his relatives or friends that know of your plans and will let you stay with them when you arrive etc. etc.
