OK, here's a learning experience for you. When you create subroutines and functions, they go into one or more code modules. Each module can be part of a form (in which case it is called a class module or sometimes a form's class module). It could also be an independent module, sometimes called a general module. Modules that are part of the form are usually set aside for code specific to that form. Modules intended to be shared are best placed in general modules.
Modules have two basic parts. Before you create any functions or subroutines, you are at the top of the module, which is called the declaration area. You can declare variables in that area, but you can ALSO define linkages to external subroutines. That "Private Declare" line is an example of a declaration of an external, library-based subroutine. By declaring it private, you make that definition available ONLY to the functions and subroutines in the module in which the declaration occurred. If you made it a "PUBLIC Declare" line in a general module, you could define it just once for your entire project. That is because you generally use PRIVATE declarations in a form's class module, and are more likely to use PUBLIC declarations in general modules - because you are more likely to share that code among multiple forms & reports.
Once you have declared your module's variables in the declaration area, you start defining the functions and subroutines for that module. VBA will complain if you make declarations in a module outside of any executable code but after the first executable element has been declared. Note that the PRIVATE keyword still works even when in a general module, so a PRIVATE variable in a general module cannot be seen from code in other modules. A PRIVATE subroutine cannot be called from outside the module. And a PRIVATE function reference is only visible to members of the module where it was defined.
