Hi, i am not experienced in programming,but i am amateur artist and like the creation ! I like and know generally how to use Gdevelop (as a noob),and would like better understand what is a good code without programming in Gdevelop 5, how optimize that !
I search someone that can give me examples of many styles of basic games, and explanations about sub events, external events, functions, and all what i must to know before start a good code ! If someone understand me, i take councils 
I am also a noob in gdevelop and as far I have discovered about optimizing code I learned
Use 1 common condition instead of repeating the same condition on various event.
suppose You have 3 groups of events and you used “At The Begining of the scene” condition many
times…so you can copy all the actions of other events and past it on a single event.
Try to avoid extension and try to use a link if you have to use the same program in each scene.
If you are making a game for mobile device and you have a huge background picture try to cut it off
in different pieces. And use them.
Try to use tween instead of animation for simple movements.
Try not to use the physics engine.
Try not to pause the scene as much as possible.
Try not to use big sprites.(Even if you scale…try to import the scale resolution)
There are many more things about optimizing games but I found this related to your topic.
thank you, i will think about that