The “nuts and bolts” of using the MB-System software package for processing multibeam sonar data collected on Autonomous Underwater Vehicles (AUVs). MB-System (https://www.mbari.org/technology/mb-system/) is open-source software for processing and display of seafloor mapping data. Surveys from submerged platforms such as AUVs and ROVs involve challenges beyond conventional mapping, including designing complicated surveys in complex terrain, addressing interference from other acoustic sources, assessing attitude sensor biases, correcting for inertial navigation drift, and merging multiple surveys collected over time on terrain that has experienced changes, such as submarine canyons and active volcanoes. This tutorial will introduce MB-System to the participants and then walk them through how to: 1. Design AUV survey missions 2. Set up MB-System processing (the “pre-processing” stage) for 3 different AUV platforms 3. Edit multibeam bathymetry data in both waterfall and 3-D point cloud views 4. Estimate and correct for attitude biases 5. Adjust vehicle navigation to match features in overlapping swathes 6. Merge surveys 7. Generate common data products, including GIS objects These steps will be shown as sequences of screen grabs and videos in PowerPoint and by actively working on example datasets. Templates of scripts we work with will be provided, and our work-flow and methods will be discussed, including of newer features of MB-System. This tutorial will focus on 1-meter-scale multibeam bathymetry and backscatter collected using MBARI’s Dorado Mapping AUVs, WHOI’s AUV Sentry, and SOI’s Hugin Superior AUV. Since MB-System supports a large number of data formats from most commonly used mapping sonars, these examples should be broadly relevant to users of other AUV or ship-mounted sonars. Participants who have experience with multibeam sonars, particularly on submerged platforms, will find this tutorial most beneficial. Novice users will come away with an introduction to MB-System and an appreciation for the complexities of working with AUV mapping data. This tutorial will NOT include installation or troubleshooting of MB-System working on participant’s computers.