Installing .DLL files is a relatively simple process. On a 64-bit Windows system, you can use both 32-bit and 64-bit DLL files. Place 32-bit DLLs in the '/Windows/SysWOW64' directory and 64-bit DLLs in the '/Windows/System32' directory.
Installing .dll files directly into the software application folder where the corresponding .exe file is located offers several advantages and is generally a safer approach than immediately placing them in the Windows system folders.
Its common to find multiple versions of the same .dll on a system because different applications might depend on different versions of a particular .dll file, leading to multiple versions being stored in various locations.