You can find lots of brokers who could provide a free demo mt4 platform to play around with while learning a system. It is also best to practice demo trading in an mt4 platform before going live. If you do not have a broker yet, you can try some free demo mt4 platform that you can download & install in your computer to play around with.
FXCM: https://www.fxcm.com/uk/platforms/metatrader-4/download/
Alpari: https://alpari.com/en/platforms/metatrader4/
These are just a few we found and we use in our demo accounts.