Hi welcome to splinterlands i can recommend a few YouTube channels that have some nice introductions:
@bulldog1205 https://www.youtube.com/@Bulldog1205/playlists
He also has a playlist with FAQ with some beginner series.

There are many more i like to watch not all have good introduction series therefor i would start with bulldog.

@infidel1258 https://www.youtube.com/c/DwayneCunningham/playlists
@stever82 https://www.youtube.com/@SteveR82_Splinterlands
@sl-guides https://www.youtube.com/channel/UC-OOmTDl1EnOAZR6LUeQVjQ
@aftersound https://www.youtube.com/@AfterSoundGaming
@hawks21 https://www.youtube.com/@Hawks21
@clove71 https://www.youtube.com/@clove71/playlists

Now also splinterlands has publish some articles that helps in depth knowledge, i prefer the more video approach iso of the reading :)
https://support.splinterlands.com/hc/en-us