Creating an object using a 3 point perspective is not as difficult as it might seem! You just need to draw the right lines at the right place and make sure that everything is accurate. Most of the objects that you will see in the real world are displayed with a three point perspective. So it's important to understand how to use this technique in your drawings!
First, create three dots on your page. Make sure that you place them in the exact order as shown above. Your shape will be easier to create that way.
Next, using the dot on the left of the drawing as the starting point, sketch two lines using a green color. Make sure that these lines are placed between the two other lines. Repeat the same process for the dot on the right using a grey tone.
Finally, using the dot on the bottom as the starting point, create two more lines using a red color and make sure that all lines are oriented towards the middle of the drawing.
Next, for each dot, create a third line that will be placed between the two lines you have drawn in the previous steps. At this point, you should be able to visualize your shape in the middle of the image.
All the black dots in the middle are representing the intersections that you will use to create your shape. The white dots are also representing intersections, but since only two lines are involved, they cannot be used to create your shape.
Here is your shape in the middle of the drawing, ready to be drawn!
And here is another version with colors to help you see it better!
That's it! Now you know how to create a simple shape using the 3 point perspective technique! No doubt that you will have to use this technique very often if you want to create a world that looks realistic enough to be believable for your readers! I hope you had fun drawing this simple shape and remember to practice a lot!
External resources: How to draw perspective