Here are the descriptions of the available checkpoints we have in Buildbox.

Set Checkpoint: set a checkpoint, that will be used for Restart From Checkpoint button.
​Next Checkpoint: move player character to next checkpoint.
​Restart Checkpoint: give ability to restart at last checkpoint.

In this guide, I have created a simple Platformer game to show a few demonstration about Checkpoints. Options are as follows:

As soon as we click create, it will take us inside the game world. On the illustration below, I dropped an image to the action portion of the Buildbox drag and drop wheel as this is what I want the checkpoint to look like.

Once dropped, you can adjust the size of the image by dragging the small squares shown below.

In the assets panel on the left, click your image so you can start editing its options on the right panel. Change the name to Set Checkpoint and select Set Checkpoint as an Action Type.

You also need to edit the Collision shape of the imported image by clicking the Edit button and changing the option to Circle. From there you can adjust the size of your Collision Shape by dragging the right most circle until you reach the desired size.

So that we don't confuse ourselves during preview, Let us align the scenes so we would know if the checkpoint that we set is working. To do that click Edit and then Align Scenes.

In order for this to work, we need to set up a restart checkpoint button in our Game Over UI. Let me show you how to do this. First click the Menu Editor to go to the Game Mind Map.

Then double click Game Over UI to open it.

Inside the game over UI, I made sure that Restart Button is selected as seen on the left panel, and I dragged and dropped a new button to the Image portion of the right panel. Now I have a RETURN TO CHECKPOINT Button.

Also, make sure that Restart Checkpoint is selected as the Function. 

Now when you preview your game and reach the Checkpoint, then unfortunately die in any of the hurdles, clicking the "Return to Checkpoint" button will take you back to where the checkpoint is.

We also have the Next Checkpoint option. The illustration below shows that the Pink image is the next checkpoint option, as soon as you go to it, it will take you the where you set up your Checkpoint is (like the blue image below). More of like warping from one stone to another.

To set this up you will have to open your game world like what was stated above when we set up the "Set Checkpoint" option. Drag and drop your Next Checkpoint image to the Action portion of the Buildbox wheel. Adjust the size and follow the options below. Now this will not work if you do not have Set Checkpoint available so make sure that you have it set up.

Instead of an item in your game, you can also use this as a button that you can press to warp to the next checkpoint. Let me show you how. Double click on the WORLD UI in the Game Mind Map.

Once open, drag an Action Button beside the jump button. See illustration below.

Now drag an image for your Next Checkpoint Button. Set Action to Next Checkpoint. Set Label scale to 2.5 (so you can see the number of available warps) and leave max refill to 3.

When you preview your game, you will see that you have 3 available warps (go to next checkpoint).

And when you press that button, it will take you to the next checkpoint where you have set up your checkpoint.

And as soon as you warp, you will notice that the number went down from 3 to 2. Remember that the number of time to use this is up to you

If you look at the below option which is found in the WORLD UI. You have an option to use it as many times as you want.

Now if you are not comfortable with a button that you can press during the game, you can also set this up so it will only show when you get to the game over screen when you die. Here are the below steps.
1.Go to Game Over UI and open it.
2.Drag and drop an Action Button to your desired location.
3.Drag and drop an image for your button.
4.set Action to NEXT CHECKPOINT
5.Label scale is to 2.5 (this is the size of your number indicator inside your button).
6.Select how many times you can use it.

Now when you die and reach the game over page, you will have the option to go to the next checkpoint. as shown in the illustration below.

You can also add another button and set it up as the Restart Checkpoint.
The step do it is the same with setting up Next Checkpoint. The only difference is you select Restart Checkpoint on the below option.