Did you have a look at the
B4XPages cross-platform projects booklet ?
When you create a new B4XPages project you must select B4XPages !
All pages must be in the project folder like B4XMainPage.
It is easier to add new pages in B4A. When when create a new page you must select B4XPage.
Currently, Add a B4XPage does not exist in B4i for technical reasons.
Enter its name and select Add module to parent folder.
All files common to the platforms should be in the Shared Files folder, like images, databases etc..
These are copied to the platforms Files folder during compiling.
All platform specific files like layouts must be in the platforms Files folder.