sim_vehicle sıtl

ı use ubuntu 18.04
ı followed all steps on ardupilot website to install sıtl however when ı try run sıtl with (sim_veicle.py -w), ı saw sim_vehicle commend not found. and ı resourch a solving and ı found
…/Tools/autotest/sim_vehicle.py --map --console --osd.
but ı have another problem. it is this.

Get into tools/autotest directory and run that python script with python3.

I just started using ubuntu. How do I run with python3 after entering the directory?

what ubuntu did you install ? as per your post here Tools/environment_install/install-prereqs-ubuntu.sh -y for SITL - #2 by khancyr . it seems an old one. Using at least ubuntu 20.04 is recommanded. if that is a fresh install, use ubuntu 22.04 and start again the installation part.

I usu ubuntu 18. 04 because i need to gazebo9 and it can be run only ubuntu 18.04. Yet, if i will can solve this gazebo problem, i install ubuntu 22.04

gazebo9 is available on ubunt20.04 and working with ros noetic