Understanding of simpletest utility

I am new to tcl and trying to understand how the following command
works .

tclsh82 simpletest SimpleProc

can some body expalin me the sequence of events ( how the test file
SimplaeProc-test is evaluated ) that happen till we get the following
result

C:\Program Files\Tcl\lib\tcl8.2\SimpleDevLib-1.0>tclsh82 simpletest
SimpleProc
Testing session run by root@suvendra at 15:20 29-Nov-2005
Using simpletest 1.0 and Tcl 8.2.3 (C:/Program
Files/Tcl/bin/tclsh82.exe)
Testing packages: SimpleProc
================================================================================

Package name version total passed failed skipped ignored
status

================================================================================

SimpleProc 1.0 169 169
PASSED

.