From Gambit wiki
Using a Prebuilt Distribution
Some prebuilt distributions are available.
Building Gambit from Source
Various distributions of gambit have been made available.
To build Gambit from source, one must first run the configure script, which has a number of important options.
There are various make targets of which you should be aware.
Snow is a package system for R4RS and R5RS Scheme. I suspect that nearly all such packages will run on Gambit. Snow has its own documentation for those who want to develop new packages, but users can simply download and install existing packages.
Gambit provides a powerful development environment through Emacs.
Termite is an Erlang-like distributed programming system written in Scheme.
Distributed computing hot right now, and Termite has been noticed in blogs and elsewhere.
Termite depends on specific features of Gambit, and at one time or another the Termite source code has been distributed with Gambit, so we point to the Termite web site from here.
People who want to contribute to Gambit development will need to learn something about how the Gambit-C runtime and compiler are organized. While we intend that source code documentation be included in the source itself (currently there is very little documentation), we intend that descriptions of program design or algorithms used in the runtime and compiler could be included on the Internal Documentation page.
Working with External Libraries
With Gambit's C FFI (Foreign Function Interface), one can easily use standard C libraries with your code; this wiki has some examples of using Gambit with external libraries