copy your sd_card.img on a micro-sd card and insert it in the board. You may have your own way to do this, but let me give you mine.
First boot: default user is
petalinuxand you set the password to p.sudo su and change the password of root
passwd root: set it to r.Allow permission to login as root: vi /etc/ssh/sshd_config and change
PermitRootLogintoyes.Reboot the board: reboot
login as root
cd /run/media/mmcblk0p1
./newdir
cd pest1
./embedded_exec.sh
Each time you run ./newdir a new ptest directory is created with a copy of the original files in it. You can edit the xrt.ini file to profile and trace various parameters.