Time Attack Racer(Episode 6): even the first checkpoint doesn't appear

I am following the Time attack racer tutorials on youtube.
I have completed episode 6, which concludes in setting up different checkpoints, which appear successively after the previous checkpoint has passed.
So my issue is, Even the first checkpoint is not appearing. I did and performed exactly as tutorials tell us to. Nothing different. As the first checkpoint doesn’t appear, I can’t pass through it and hence the next checkpoints don’t appear as well.
I am a newbie to Unreal Engine and can’t figure out the solution. I hope you can help.
Here’s a link to the video: