Everything is clear here. You choose a broker, register and open an account. The account can be opened in a specific currency, so decide in advance which one it will be – USD, EUR, or GBP (or it could be another from your broker list). Almost all brokers are offering to make a deposit with a payment card VISA or MasterCard. Please note – not all of them accept VISA Electron and / or Maestro.
Bank transfer is also accepted, but you should pay a commission to the bank.
Sometimes deposit using e-wallets are offered. Among the most popular e-wallets is WebMoney. Or such e-wallets like QIWI and Yandex.
Withdrawals: the safest and fastest way – to the e-wallet, and many brokers will offer this to you.
Check, which side covers the fees for deposit and withdrawal. Usually it is on the side of brokers, but there may be exceptions.