All files are available on github at https://github.com/echeever/BodePlotGui
Directions on how to use BodePlotGui and interpret the results are in BodePlotGui.html. To use the BodePlotGui tool you need two files, BodePlotGui.m and BodePlotGui.fig . That are available on Github. Both of these files must be on you hard disk so that they are in the MATLAB® path. Download them and save them so that MatLab can find them (from the Matlab menu go to File->Set Path and include the directory where you stored the files.)
To help in learning to sketch Bode diagrams by hand, it is helpful to have semilog paper for the magnitude and phase plots. The file BodePaper.m is a MATLAB® tool that will generate such graph paper. A description of how to use it is in BodePaper.html, along with some examples. Alternately, you can get help by typing ">>help BodePaper" from the MATLAB® prompt after copying the file on your hard disk, in the MATLAB® path. An example graph is shown below.