I would recommend learning the great plateau any% run first from limcube's tutorials (Listed in the guides tab) along with other resources. Also be sure to join the BotW Speedrun Discord if you have any questions. Best of luck to you!

Limcube's tutorial is awesome for beginners it helped me alot

Also you could try Bug Limit. LouLouCore is making tutorials on it

YT channel of Zelkys contained also some tutorial and he begin a new series few weeks ago : https://www.youtube.com/playlist?list=PLhOHTShC8V-DXyEltNoVYhz1Xx2TQ8OKv

Also for french speaker, you can check YT channel of Aife : https://youtube.com/playlist?list=PL5KiMRVZeiNKNWNk8BsUx69DBPKHCRadO