Introduction ============ This tutorial provides an introduction to the use of |RELION|-3.1 for cryo-EM structure determination. This tutorial covers the entire single-particle analysis workflow in |RELION|-3.1: beam-induced motion-correction, CTF estimation; automated particle picking; particle extraction; 2D class averaging; SGD-based initial model generation; 3D classification; high-resolution 3D refinement; CTF refinement and higher-order aberration correction; the processing of movies from direct-electron detectors; and final map sharpening and local-resolution estimation. Carefully going through this tutorial should take less than a day (if you have a suitable GPU or if you follow our precalculated results). After that, you should be able to run |RELION| on your own data. This tutorial uses a test data set on beta-galactosidase that was kindly given to us by Takayuki Kato from the Namba group at Osaka university, Japan. It was collected on a JEOL CRYO ARM 200 microscope. The data and our precalculated results may be downloaded and unpacked using the commands below. The full data set is also available at EMPIAR-10204. :: wget ftp://ftp.mrc-lmb.cam.ac.uk/pub/scheres/relion30_tutorial_data.tar wget ftp://ftp.mrc-lmb.cam.ac.uk/pub/scheres/relion31_tutorial_precalculated_results.tar.gz tar -xf relion30_tutorial_data.tar tar -zxf relion31_tutorial_precalculated_results.tar.gz If you have any questions about |RELION|, first read this entire document, check the `FAQ `_ on the |RELION| Wiki and the archives of the `CCPEM `_ mailing list. If that doesn't help, subscribe to the CCPEM email list and use the email address above for asking your question. .. caution:: Please, please, please, do not send us direct emails, as we can no longer respond to all of those.