Tips:

Subpatches: Many of the buttons in MaxOrch open subpatches that allow you to make important adjustments to orchidea's behavior. Each contains an explanation of the settings they modify.
Once you've gotten the hang of creating basic orchestrations, move on to the Settings. Open the "More About Parameters" subpatch for info about each parameter.
Static vs. Dynamic orchestration: this is controlled with the onsetthreshold setting (on right, near top). Set to 1 for static orchestrations, <1 for dynamic.
The Solutions Grid (located in the View Solutions subpatch) has several views available from the Select Grid View box. Try them out to see which is most useful.
When running a dynamic orchestration, you can choose to see every generated solution for every segment in the graph. Keep in mind that Orchidea will choose one solution per segment to stitch together to create the connection.
About the notation objects (bach.roll and bach.score): to play back your solutions directly in either of these, click on the score to select it (the border darkens slightly) and hit the space bar. Volume is controlled with the faders in the upper corner of each.
To fix this error: “orchidea.solve: error: orchidea: orchestration error (empty orchestra; please check filters),” start by turning off partialsfiltering (in the paramaters column on the right side, uncheck the box). If this fixes the problem, you can recheck it and then try adjusting the partialsfilteringthresh parameter.

Glossary:

Connection - Orchidea's guess at a best solution (in a static orchestration), or combination of best solution per segment (in a dynamic orchestration). This guess is based on the connection policy as set by the @connection attribute in the orchidea.orchestrate object.
Database - Contains analysis information about the sounds in a given sample library.
Dynamic orchestration - An orchestration of a sound that responds to changes in the sound over time. Before each orchestration, a segmentation step divides the original dynamic target into a set of static targets to optimize. Finally, a specific model tries to connect the generated solutions into a single score.
Epoch - One generation of solutions as generated by Orchidea's genetic algorithm.
Sample library - The library of instrumental (or other) sounds used to create the .wav solutions.
Static orchestration - An orchestration in which the target sound is considered a single average timbre in time and no onsets are considered. The outcome of a static orchestration is a single chord.
Solutions - Results of an orchestration. There are as many solutions generated per segment as set by the "maxexport" parameter.
Styles - The list of playing techniques available in a given sample library/database. Can be filtered by the user in a given orchestration.
Target sound - The audio file fed to Orchidea by the user for orchestration.