Splinterlands is a really great game. First of all, you can get preliminary information from this link https://support.splinterlands.com/hc/en-us/categories/4412362838804-FAQ
Afterwards, you can log into Splinterlands and fight practice battles for free. You can also review the how-to-play app on the main page. These will be enough for the beginning, you can ask me again for more.