Files can downloaded from the Files section in the Sourceforge site. That section contains links to various different versions and releases of Maxima.
Get the most recent version from the Maxima-Windows subsection, which will be a single file with a self-contained installer program.
In Linux distributions based on RPM packages, enter the Maxima-Linux
subsection and follow the link to the most recent version. The
page will contain several RPM packages named as:
name-version.i386.rpm, where the first part is the
name of each package and the second part are the numbers that
identify the version. The minimum set of packages that must be
installed are maxima and maxima-exec-clisp.
Since they both depend on each other, they should be installed
with a single rpm command:
rpm -ivh maxima-x.y.z-n.i386.rpm maxima-exec-clisp-x.y.z-n.i386.rpmClisp and Gnuplot should be installed in your system.
You may also want to install maxima-xmaxima, which provides the Xmaxima graphical interface and a graphics program needed by some commands such as plotdf and ploteq.
The maxima-lang packages provide translations of the manual into various languages.
Get the most recent version from the Maxima-MacOS subsection, which will be a single package.
The download instructions and links can be found in the Maxima on Android page.
In systems not included in the previous list or, if you want to build a more recent Maxima version or with a different Lisp flavor, get the source code from the Maxima-source subsection. Unpack the file and follow the instructions given in file INSTALL, which can also be read on-line.
The most recent development version of the source code can also be downloaded from the GIT repository. That page shows the git command that should be used to obtain a complete copy of the repository. After getting the code, follow the instructions in INSTALL.git.