Regarding the investment size, start with an amount you can afford to lose. (i.e. : You do not need to pay your bills with it or your rent/mortgage).
Start with reading info on internet from various sources, read the pros and the cons.
Follow some excellent Youtubers
Read the whitepapers on the coins you want to invest in
Open an account on Coinbase/Bittrex and then buy various promising coins.
Buckle up and enjoy the ride
Reinvest the profits in more cryptocurrencies when they are low (or cash out)
HODL and chill