I am always very pleased when users of the Semi-Automatic Classification Plugin wish to contribute to the plugin community and write tutorials about the use of this tool.
Mônica Pacheco de Araújo, a biologist at the CNPq junto ao Núcleo de Estudos Ambientais da Universidade Federal do Tocantins, has written a very useful tutorial in Brazilian Portuguese about the classification of Landsat images in the study area of the Basin of Ribeirão Mutum.
The tutorial describes the steps from plugin installation, to download and processing of Landsat images, to the accuracy assessment of classification.
The tutorial is available at this link http://qgisbrasil.org/blog/2015/08/18/qgis-classificacao-supervisionada-de-imagens-orbitais-com-o-semi-automatic-classification-plugin/. In particular, a PDF file of this tutorial is available here.
Many thanks to Mônica Pacheco de Araújo for the valuable contribution to the user community, and to the blog qgisbrasil.org that hosts this tutorial.