How do I start my own clothing business?

Hi! I'm a high school teen, living in Canada (if that makes any difference) and my friend and I were thinking of starting our own business! Although of course, having no experience whatsoever nor mentors, we don't know where or how to begin. We started thinking maybe just selling little stuff like keychains, phone cases and socks (big emphasis on the socks) with our little logo to make ourselves known and build up a little more money for future ideas.

Those ideas consist of :

1. Making apparel with cool (imo) designs on them. (Tees, Long sleeves, Sweaters, skirts, dresses)
2. Making genuine leather belts and those trendy Off-white like belts.
3. Making backpacks and purses.
4. Making pants (jeans excluded).
5. Making accessories.

omegleFor these to happen we need to know

1. An easy design software and the tools we'll need to perfect our designs (tablets or so).
2. Where to buy the plain clothing or ask to make it (let's say I want an asymetrical skirt, I can't find that on Gilden.)
3. How to build our website and what order managing add-on (?) we need to place orders.
4. On what website can we print the designs for cheap and well (embroidery and like paint? not the plastic stuff). I saw some but I didn't have freedom on where to place the design I wanted.
5. Where to design hair tie, bobby pins (not just the colour but really the shape and dimensions) and hair clips.
6. How much money do we need to get started and how much do we need to charge more (%) to have a good profit and keep it rolling.

Also, is there anything we should be wary of? Such as financial planning, shipping details, ads, management? Should we hire people to help?

Could it be possible with our demands to do it ethically? Like maybe in Canada, Europe, the States, etc.

(I know very well this might sound lazy to ask so much but I tried to do my research but I don't know why I felt so.. lost? Like nothing was going well. )

I did a few hundred sketches in my sketch book and I'm looking into ads too.

If you have anything additional to say it is welcome and I would really like it if you had any tips and tricks or anything to correct or such. Please be as harsh as possible. Thanks a lot for reading. Sorry for my english as well, I'm from the French-Canadian part of Canada therefore my english isn't as good. Have a great day!