In order to be able to view and navigate the EMMO ontology we recommend to download the Protégé editor from https://protege.stanford.edu/products.php#desktop-protege.
See these instructions for how to set up Protégé for working with EMMO-based ontologies.
The fastest way to access the EMMO is to open the ontology via Protégé via the menu under File -> Open from URL... and copy the URL https://w3id.org/emmo: Protégé will automatically download all the necessary dependencies.
The EMMO hierarchy will be visible only after reasoning inference: use ctrl-R to start the reasoner and under the Entities tab, select the Classes subtab and Inferred in the scroll button.
From EMMO 1.0.0 it is recommended to use HermiT as reasoner (distributed by default with Protege). For earlier EMMO versions is FaCT++ the recommended reasoner. You can select it through the menu Reasoner. An instruction for how to install the FaCT++ plugin on Protege 5.5.0 on Windows can be found in the doc subdirectory.
To access EMMO from Python, we recommend EMMOntoPy (former EMMO-python).