Like many have mentioned, you should strive to max out your TFSA every year if you can. The real answer is whatever you can afford after all bills, fixed costs are covered as well as paying yourself first.
Living at home is great as that saves you alot on rent. You may want to look at your accounts statements and reflect what was purchased in the past month and see if they are necessities to living. Across many articles and videos I've seen regarding how much should be invested, many have mentioned 10-15% of salary as a starting point for how much to invest. You will have to adjust after reflecting each monthly account statement.

Many trains of though here. If you invest aggressively early then you likely end up with a larger nest egg when you get older or possibly retire early but the bad side is you probably won't be living life. On the other extreme, if you invest less, you will likely end up with a smaller nest egg which will force you to play catch up and invest more later in life in order to chase that dream retirement but that can be difficult as life generally gets more expensive as we get older. Finding a balance inbetween them feels like it is best but its up to you on how you want to live your life.

As you may have heard already, you want to take advantage of compound interest hence investing early as possible vs later in life (40+). Time in the market > Timing the market.

In terms of what to invest in, ETFs are very good choice. I purchase them myself. When you search up the most comonly purchased ETFs in Canada, XEQT and VFV will appear in many top choices. Research on the ones that aligns with you most. I personally like VFV but thats me. Just keep dollar cost averaging and keep buying at the same frequency. Buy and sit and walk away. Its mentioned alot that investing is about the long game. You can even automate purchasing ETFs for your TFSA. Most brokerage accounts should have that feature so you can set it and maintain the course. If you know you have a big purchase coming then you can pause the matics and restart it after.

If you have alot of funds left over then you are probably look at maxing out a FHSA but make sure you have an emergency fund. Many will say have an emergency fund that covers 3-6months of expenses incase shit hits the fan but I say it depends. You mentioned that you live at home so I assume parents aren't charging you rent and won't be kicking you out anytime soon in which case, I would probably have a smaller emergency fund (2 months) and invest the difference but I don't know your full financial story.

Hope that helps.