First create your workspace and enter it:

mkdir rrt_ws/src
cd ~/rrt_ws/src

then clone it:

git clone https://github.com/wrld/ROS_RRT.git

then make it:

cd ~/rrt_ws
catkin_make
source devel/setup.bash

then launch it:

roslaunch nav_sim myrobot_world.launch 
roslaunch nav_sim move_base.launch

pick the goal point, and then you will see the simulation.

vim nav_sim2/cfg/new.yaml

Change the value of choice to change the method:

• 0---rrt based on probability
• 1---rrt connect
• 2---rrt*

Change the value of gravity to set if using gravity of the goal point:

• 0---no
• 1---yes

Change the value of smooth to set if smooth the road:

• 0---no
• 1---yes

and more parameters to change the steps or probability.