simap4.el is an elisp library intended for use by Emacs elisp programs, to connect and exchange internet messages with IMAP4rev1 (RFC 2060) Servers. It is assumed that the library is used by MUA programs which run on Emacs. Only default authorization method is supported, and it's just to convert IMAP4rev1 commands and responses defined in RFC 2060 to lisp forms for easy use with Emacs lisp programs.
simap4-console.el is a command line based user interface to execute simap4 functions and run as a major mode on Emacs. A purpose of this program is to help debugging of simap4 library.
Since there are only few files (essentially only simap4.el), manual copy and compilation would be the fastest way to install. Make a directory with appropriate name like simap4, and copy simap4.el there. To compile, a simple way is to use dired mode, and type "B" (dired-do-byte-compile) on the line of simap4.el. If you want to install simap4-control.el as well, do the same procedure as simap4.el.
make (Unix) and makeit.bat (Windows) may be used to compile and install. To use make, edit EMACS and INSTALLDIR in Makefile as appropriate for your environment, and run make install. To use makeit.bat, copy makeit.bat to a file such as %HOME%/.elispmk and set necessary environment variables (PREFIX, EMACS, EXEC_PREFIX, LISPDIR, INFODIR, VERSION_SPECIFIC_LISPDIR) and run ./makeit.bat install. Please refer to the header comment part of makeit.bat file, where more detailed information can be found.
Since simap4.el itself is a program library, there is no user visible usage. For usage of functions defined in this library, please see simap4.el and RFC 2060.