Multiple hot spots find them all question

It's not clear to me if you want a graded question that tests whether the user can pick out all the hazards or if you just want an interactive slide. 

A Freeform pick-many question would work to test whether the user can click/select all the hazards.

• If you do this, I suggest you use 99%-transparent shapes (not hotspots). Shapes can have states, so a Selected state could make it obvious if the shape has been clicked.
• This type of graded question doesn't provide info about each clicked item when it is clicked. You could put all that info into the feedback layers (though I'm guessing that would get crowded).
• Here's more info about Freeforms: https://community.articulate.com/series/articulate-storyline-360/articles/articulate-storyline-360-user-guide-how-to-convert-existing-slide-to-freeform-interaction 

If you want to show info about each hazard when the user clicks on the area, then I suggest using the same type of 99%-transparent shapes. Give them triggers that show a layer with the corresponding info. You could have shapes over non-hazards, with the corresponding layer explaining why that's not a hazard. 

• Insert the image
• Add hotspots
• Create a layer for each hotspot
• Add a trigger to the layer from the hotspot
• In the layer add the dialogue. Add an exit option to hide the layer, if you want.

The steps are easy:

• Insert image
• Insert hotspots where you want them
• Figure out how you want to display the information for their selection. I would use a layer.
• Add a trigger to show layer X when hotspot is clicked.

I created a tutorial to show the basics and a few bonus tips.

https://360.articulate.com/review/content/6d8e76e8-83b1-479d-9545-55a2427b9f6e/review

As to button sets, forget the term button. Any items can be made into a set. Button is just a term of convenience. Select two or more items, right click, and choose Button set. Some things to remember:

• Only one of the set can be selected at any time
• Once one of the set is selected, you cannot deselect it except by selecting another
• Items will not show which is selected if they do not have a Selected state, unless you create another state and triggers to show it.
• There is no way to select part of an image, whether you want to click it, or use it as part of a set.
• An item can be part of only one set.

They are irreplaceable if you must have what they offer, but can require a lot of resource investment, if they are used just for fun.

There are some ways to easily make part of an image clickable.

The most glamorous (least useful, and most difficult) would be to insert a number of copies of the image. Crop them the smaller rectangles, and put the rectangles together, like a jigsaw puzzle. Each piece would be an independent object, and could be treated independently.

Easier methods are suggested by Tom and Judy: hotspots or shapes above the image. Remember, this is a visual medium, so nothing has to do what you want. It only has to look like it is doing it. If a learner clicks on an invisible item above the image, they think they are clicking on the image.

For what it's worth, I favor Judy's method of shapes. Shapes, without the baggage and limitations of hotspots, give me a lot more flexibility.

The attached sample shows two fairly simple ways to do what you are asking; one using states, and one using layers. Both of them show how they might work if the clickable spots are a set, or if they are not.

Yes, this is a business that requires a lot of painstaking attention to (sometimes) tedious detail, but that's what separates great results from good enough.