I have little idea how to start. I’m learning Unity and Blender, but every time I watch a tutorial, it opens up a whole new area (like particle effects, physics) that I have to learn just so I can understand the tutorial. It’s like learning calculus, then realizing you have to learn algebra II, then geometry, then algebra I, then basic math. I mean, I can create a mesh object, slap a texture on it and so forth but how do you draw all the parts together into a whole?
I’m starting as basic as possible. My idea is to create a skull and facial muscles that would be a teaching tool. I want to include text descriptions of the muscles and bones.
Well, it seems you would need to make your models first in Blender. Then you will need to figure out your input schemes, and the reactions they create. Example, mouse clicks the jaw, the jaw animates, mouth open. Perhaps a little information window appears as well, describing what is happening. Then, if you tap another area, the jaw stops animating, resets to mouth closed. They information window closes. Then the new area animates, its little info window pops out etc.
This is a cycle.
I think your main unity concerns are your inputs and reactions. I would create a manager that knows what area is active. It also knows each area. I would also create delegates which act as inputs to the areas. When pressed, they would start their designated animation, open the pop out info window and tell the manager that this area is active. The manager logs that, as such, next time an area is selected, the manager knows to close the area that is currently open and of course now, logs the area that is now active.
- Figure out what you want to do.
- Figure out how to do that.
- Do that.
When there is nothing left to figure out, you’re done.
As easy as that! 
No really, go step by step, don’t try to go the full way with just a single jump. That’s just too much and will make you get rid of any possible motivation, especially as a beginner.
Make small goals and try to achieve those first. Try to start with the modelling of any kind of model in Blender, and then try to import that into Unity. Then have a look at materials and textures, how they work together and what needs to be done and so on and so forth.
You need to know many things for developing a game. Here is what you want to know. Of course things will get thinner than that, depending upon your targeted quality.
Did not cover animation and rigging so much. Hit me,if you are curious of what we do in these two fields or in others.