If you have the space, it works well to store your STEM supplies either by type of resource or by type of challenge.
We use the closet in our filming studio to store our STEM materials and we also have a large shelf in the garage where we store things. I like to store them by type of resource, so we have LEGOs together, science experiment supplies together, microscope stuff together, building materials together, and so on.
I bought little dish tubs to store our items in. You could also use stacking containers, but I found that when we stack supplies, no one puts them back, so we use open containers in just one row.
That way kids can just toss things back into the appropriate bin when they are done with them.
You also should have a cleanup station with tons of paper towels, rags, and a trash can. These STEM activities can get messy, so having some tools to make clean-up easier will help a lot.
Most of all, the place where you put your STEM center should be welcoming for kids to do explorations on their own! Put a computer or tablet there so they can do coding on the computer (and watch their Jarring Science Lessons!).
This can help facilitate the lessons and help them be able to access information and facts about their experiments as they are learning.
And make sure you teach your kids and students how to put things away when they are done. Nothing hampers the scientific process more than a big pile of mess to clean up before you can even get started!
As a parent or teacher, you want your child/students to succeed. Adding more STEM learning for your children is a way to help them become problem-solvers, innovators, and critical thinkers.