How to send transcripts

Hello, im an incoming freshman (international).
The portal says to use Parchment, Naviance, National Student Clearinghouse, or JST DoD Military Transcripts to send transcripts, but im not sure how to actually use them…?
Do I just tell my teachers this? Or are there other ways to send transcripts? (Im the first student in my hs to study in the states, so my teachers probably dont know much about it…)