DMLite is mainly a software stack for developers, and its technical documentation is maintained as a set of Doxygen pages.
To install the technical documentation you have to install the
dmlite-docs
package from your favourite repository (normally EPEL, EPEL-testing, release candidate, trunk).
After having installed the docs, point your browser to the file
/usr/share/doc/dmlite-<RPM version>/api/html/index.html