Help to set up the simulator gazebo

hi
I installed these items :

ubuntu 16.04
ros kinetic → install Deskop-full

I have these items :
quadcopter :
pixhawk
raspberry pi 3 → os = ubuntu mate - ros kinetic
camera module raspberry pi 3
and …

What i want to do :
First :
Launch the simulator
Connect to Quadrotor made with Mavros
Send commands for operations like takeoff and landing, or … (mavros)

Give me a general guide

Have you seen the ROS and MAVROS documentation?

https://dev.px4.io/en/ros/mavros_installation.html
https://dev.px4.io/en/ros/mavros_offboard.html

There is a recent change - Gazebo 8 is the default gazebo for Kinetic now.
I had major problems trying to resolve this.
Remove Gazebo 8 (ROS package) and install Gazebo 7.
I specifically did it this way:

  1. Install ros-kinetic-desktop (NOT FULL)
  2. sudo apt-get install ros-kinetic-gazebo-*
  3. sudo apt-get install ros-kinetic-mavros*

SO this allows it to work (using the ROS simulator docs on px4 dev).
But i cant get it to work for a custom environment (using no_sim=1 make posix_sitl_default).

Any ideas on this?