@Ixsyn I don't know about creating save points but until you learn I just wanted to help with an alternative way.
If you are using Menyoo, place the vehicles you want from the Object Spooner section (Not the vehicle spawner). You can also customize your vehicles as well. Once you are done with placing your vehicles (and any other stuff if you wish), go to Object Spooner again then Manage Saved Files > Save Database to File. Then you will give it a name and set the point where you would like to spawn (save location basically).
Now every time you load that save, it will place your cars and anything else you spawned with Object Spooner to their locations and will teleport you to the spawn location. If you wish, you can turn that option in settings and manually teleport yourself to your saved position as well.
I hope this helps you until you learn how to add proper save points )