Team leads, or tech leads, usually shift into a team member or ScrumMaster role, depending on the skills and attributes of the individual. People skills are important in this role. ScrumMasters must be facilitators who can guide self-organizing teams without having authority over them. Being a ScrumMaster is about providing guidance, not answers.
Core courses are fundamental to your effective use of agile.
Recommended courses are a great way to expand your agile expertise.