To run programs that use the LablTK GUI, the directory where the
DLLs tk83.dll and tcl83.dll were installed (by the Tcl/Tk
installer) must be added to the PATH environment variable.

To compile programs that use the LablTK GUI, the directory where the
libraries tk83.lib and tcl83.lib were installed (by the Tcl/Tk
installer) must be added to the library search path in the LIB
environment variable. E.g. if Tcl/Tk was installed in C:\tcl, add
"C:\tcl\lib" to the LIB environment variable.

以上を呼んだのですがpathの追加方法がよくわからないので
どなたか、わかりやすく説明していただけないでしょうか。