The first step is choosing which instance or community to join, just like on Discord. To see the available options, go to joinmastodon.org. This can also be done from the apps available for iOS and Android. It is possible to choose the community based on the topic of interest, language, or number of users.
The first server that was created is called Mastodon Social and it is found here. There you can see, for example, the rules of that community that, among other things, prohibit expressions of racism, sexism, transphobia and xenophobia; as well as incitement to violence or harassment, among other things. As can be seen, the fact that it is an open community does not imply that there are no rules, but rather that the rules are set by each community.
Once the instance to join has been chosen, you have to register as on any platform, including username, email and a password. You will receive a confirmation email by mail and then you can enter the site.
In the case of the web version, you will see three columns: one where the posts can be published, another to see publications and the third where there is a menu with different options to track content, notifications, etc.
When making the publications, users can also be mentioned by grabbing them and using hashtags. In fact, there is an option called “Explore” (in the right column) that allows you to track thematic content through hashtags.
It is possible to add warnings to posts, such as “spoiler alert” if something about a movie or series is going to be mentioned; as well as choose if you want the content to be public or only for some followers.
It is important to note that Mastodon has three timelines. On the one hand there is the main timeline, which shows the messages of all the users that are being followed. Then there is the local timeline, which shows the messages of the members of the instance to which one belongs. Finally, there are the federated stories, where the contents of other instances can be read.
In the event that the user does not find a community that interests him or for whatever reason he prefers to create his own server, he can do so using the source code found on Github. Documentation and support for this type of development can also be found from the main Joinmastodon page, mentioned previously.