I wish I knew how to do it. Everytime I try I hit a roadblock because it won't let me go further with the stock app.
Um, get a decent, low cost broker.
I use Saxo bank, but if you are Murikan you have a lot more options.
Read a bit more on stock trading, I recommend
The Intelligent Investor as a starting point, other decent books you can read up on are listed in the Alternate Investing thread on here.
Usually there are demo accounts and the like that you can use.
Do not rush in, do not get pissed about losing an opportunity, read up on stocks, etfs and bonds before you go in the market, play some with a demo account with virtual money and learn what type of investor you are.
Most importantly though, stay the fuck away from crap like "social trading" and scummy apps with gamification.
Investing must be boring if you are doing it the way Graham described.
Read the latest revision of the book I mentioned, maybe a few times, find what type of investor you want to be, and don't let the media or gurus deter you from your goals and preferences.
Basically the best Value Investors, IMHO are asocial nerds that do not let a leming mindset or mindless chatter deter them.
I'd read up on Buffet and Mike Burry if I were you, the big short, the book, not the movie, is a good place to start.