Open a text editor and find the ▶︎ unicode symbol.
It will be called something like:
BLACK RIGHT-POINTING TRIANGLE
Unicode: U+25B6 U+FE0E, UTF-8: E2 96 B6 EF B8 8E
Open a sequence in premiere and create a text object.
Keyframe the opacity to 100%
Move forward 15 frames
Keyframe the opaticty to 0%
Select the two keyframes
Right click them and set them to &...