No books can prepare you; just don't go on bitmex; you will be rekt.
I agree with the part of: " No books can prepare you " but what has bitmex? Did I miss something?
This is not a very good idea. It cannot make you many money if you day trade. It might costs you a lot if you don't have the idea in trading.
this is good advice, OP said he just wants to learn, so he will not risk doing day trade with a lot of money. I hope
Im not goin to start day trading now, i just want to learn about it before that, some knowledge about that how works the market and maybe after that i will try 
Best option would be to buy many coins and hold for a long time
I already have good coins holdings as metronome, wan, NEX and icx. But i have some other money in ETH and BTC so my idea is to increase them, i dont want to trade with fiat pairs or USDT, i prefer some pairs between alts and btc or eth and other alts, its seem for me harder to loose in usd value that way.