Open the pdf file (below) to see pictures of the carry, rest, and play positions for your instrument. The instruments appear in score order so keep scrolling down until you find your instrument.
Marching Basics and Basic Commands for Parade Marching are self-explanatory.
Check out how to do the Wheel aka Gate turn on parade:
Parkersburg High School Band Wheel Turn
https://youtu.be/YpBIrJhsbLs?si=IowAxEGfboWk2rYn
https://www.thebeatgoesonmb.org/marching/paradecorner.htm