I've made special a folder called blueprints and then inside that folder I have made a couple of blueprints (see picture on the left). Also I made another folder inside the blueprints folder named 'UI' and inside that folder I've created a widget blueprint.  I have done this so i can keep my files nice and tidy.

After creating MyPlayerController i went into VehicleAdvGameMode and set the player controller class to MyPlayerController.

Afterwards when i was satisfied with my race tracks I created some blueprints which i will need in order to create my game. 

I then went onto MyPlayerController and did all the prep work, got all the variables, functions etc ready so i have everything prepared for when i will be using them.

 I went into the Checkpoint blue print and created a arrow, the reason for this is to only allow the checkpoint only to be passed if the played goes through it the same way the arrow is facing, so the checkpoint cannot be passed if e.g. the player drives through the back of it.
I then added a trigger box in order to make the checkpoint , i resized it and then placed the arrow in the middle of it. I've also added a particle system, but im yet to work on it.

Here is a picture of the checkpoints in game, if you look closely you can also see the arrow in the middle of it, in the bottom right corner of the image. This image also provides a different shot of how my game looks like. The red arrow is not visible in game, only in the editor unlike the trigger box as it needs to be visible in order for the player to know where it is. 

I've also created the blueprints that will allow the checkpoint system to work.