SIM800L installation vcc RED

hi i am new with the arduino for iOT
i have difficulty about providing vcc current 3.7 - 4.2 V with 2000 mA (i know this from googling every where). Some youtuber in this video : SIM800L: Making Calls and Sending SMS - YouTube
use same sim800L and diode between 5 v and sim800V
my question is what is the diode should i buy ? because youtuber do not give me explaination

Sim 800 needs a lot of power.. more than your arduino can provide.
Add a separate powee source: A cell phone battery ? or: A cell-phone charger (5v) and one (or two) 1A diodes in series, (to drop the voltage to a safe level) A diode like (standard) 1N4001 can handle the current )