Congrats, you have made the decision to invest. Now, where do you start? The amount of information can we overwhelming, so here below are a couple of links to help you get started.
Important to check with brokers are the fees (both in $ dollar and in % of the value of the transaction), e.g. of brokers are Interactive Brokers, De Giro, Charles Swap, Morgan Stanley, Fidelity, a good article from Investopedia that goes into picking your first broker.
..(there are a lot of apps, pick the one you prefer)