Hi @José Eduardo Pelcastre Ramírez, 

I personally recommend you to learn salesforce 

admin beginner module, it would definitely help you to understand the basics of salesforce and how salesforce features work. Here is the link:  trailhead.salesforce.com/content/learn/trails/force_com_admin_beginner

After completing the beginner module you should move to 

admin intermediate module. In this module you will learn more about the advance concepts of salesforce admin. Here is the link: trailhead.salesforce.com/content/learn/trails/force_com_admin_intermediate

Good luck in your salesforce journey.