To BYOFA you will need an online broker. I've linked to a Money Sense comparison of online brokers in Canada. There are a couple of things to consider.
BYOFA advocates a buy and hold strategy utilizing broad market, passively managed, low-cost Exchange Traded Funds (ETFs). Buy and hold strategies imply that you won't be trading much. Consequently, cost per trade is less important compared to an active trader.
All the main banks in Canada have their own online banking platform. Your first platform to consider should by your bank's online platform. There isn't much difference between the major banks platforms.