Sometimes it is handy to start an application right after boot time. This is how I did it, to start chromium-browser in fullscreen mode.

cd .config
mkdir lxsession
cd lxsession
mkdir LXDE-pi
cd LXDE-pi
nano autostart

This is the autostart file: Autostart

Another autostart file, which hides the "Chromium didn't exit ... " blah blah blah Autostart

To hide the mouse pointer install unclutter:

sudo apt-get install unclutter

Then add this line to the autstart file

@unclutter -idle 0

Another autostart file

nano .config/lxsession/LXDE-pi/autostart

@lxpanel --profile LXDE-pi
@pcmanfm --desktop --profile LXDE-pi
@screensaver -no-splash
@lxterminal -e /usr/bin/python3 /home/pi/

Yet another way to autostart OpenCPN

@lxpanel -- profile LXDE-pi
@pcmanfm --desktop --profile LXDE-pi
@xset s off
@xset -dpms
@xset s noblank