I recently learned about discourse, and I’d like to develop my own discourse for my website, where parents can come and discuss different topics. I really like Stem Away’s website and want to know how it was done so I could base my community on their format. How can I do this?
Hi there 
welcome to Meta
That looks like a very customized discourse site. I expect you would have to build it or hire a developer to do it. It isn’t a template theme, or a simple install of components and plugins.
Hi and thank you for welcoming me
Gotcha, so how can I learn about discourse to the point that I could develop it myself? What are some awesome resources that I can learn from is a step-by-step way?
Can start with these. Also search works pretty good here, especially in the Documentation category.
Awesome, thank you so much! 
Where can I find themes that I can use in the mean time while I’m working to develop this?
Perhaps try the Customization > Theme or Customization > Theme component categories?
Thank you very much!!
They use several custom plugins that they’ve developed over the past several years. They have a bunch of things that I think you don’t need, like a resume builder and some other things that I’ve not paid close attention to.
If you say you want a site like theirs, then you need several years and tens of thousands in development costs.
But you don’t really want a site like theirs. Their’s doesn’t have any support for parents that I’m aware of. The first thing to do would be to identify exactly what things that they have that a stock Discourse site does not have and then look for how to do that.
Then you can see what those changes are worth to you and then look for a solution that fits your budget. When you’ve done that you can contact me or post in Marketplace.