I've coded a Visual Studio 2015 game in SDL2 and ran some distribution tests, I gave a user the game's .exe (the raw game with no files) and they got the error SDL2.dll is missing. How would I export the game so it includes the least amount of rubbish (visual studio) files and doesn't produce these sdl errors.
To test your installer - which you build with any of the many installer tools your favorite search engine suggests - you should use a clean virtual machine. Anytime you test the installer, you first reset the machine to it's initial state. Such a reset removes any changes made by a previous run of the installer, including things that are easy to forget about, like registry settings or the visual studio redistributable package.
So what you are looking for is some type of an installer-builder. You need something that takes the DLLs your game relies on, the game executable and all the resource files that your game loads in, and packages those into a single installer file, which will then extract all those files to the directory specified by the user. There are multiple systems that allow you to do this, I personally only have experience with WiX Toolset. An installer also allows you to reference VS Redistrubutables, which will be installed on the user's machine if they are not found.
An alternative to this would be to use a zip-file, where you manually copy the DLLs, resource files and the game executable. This way the user can just extract the package to a directory, and run the game. This however doesn't guarantee that any redistributables would be installed on the user's machine.