To start, you need to open a demo account on any MetaTrader 5 (MT5) Broker of your choice. If you do not know any MT5 Broker, just search for "MetaTrader 5 Broker" in your favorite search engine. If you do not want to register a demo account with a broker, you can simply download MetaTrader 5 on the official website.
MetaTrader is designed for Windows, but there are ways to install it on other operating systems like Linux or macOS using PlayOnMac or PlayOnLinux.
Download a Trading Robot of your choice to your hard disk. All Expert Advisors and indicators have the file extension ex5. Open the directory where you have installed Metatrader 5 and copy the file into the MQL5/experts folder, then restart MetaTrader. After that, you will have access to your new Trading Robot inside Metatrader 5.
Once you have downloaded and installed your EA, you need to optimize it for the symbol and timeframe you want to use it on. For this, we use the integrated Strategy Tester. You can open the Strategy Tester by typing Ctrl+R. A detailed guide on how to use the Strategy Tester will be available here in the future.