# How to join ACDH Mattermost

Mattermost is a messaging platform which allows a team to communicate via thematic channels or direct messages between members, all in its own, dedicated workspace. ACDH has adopted Mattermost as its preferred way of team communication and provides a self-hosted instance as as service to its cooperation projects. 

Please follow these instructions to become a member to your project’s Mattermost team:

## 1 Register at gitlab

ACDH Mattermost uses GitLab for authentication. Going to <https://gitlab.com/users/sign_in> you can either create a new gitlab account or log in with your existing [GitHub](https://github.com), [Google](https://google.com), [Twitter](https://twitter.com) or [Bitbucket](https://bitbucket.org/) credentials. Further on, you will use these credentials to access Mattermost.

## 2 Becoming part of the team

Announce the email-address associated with your GitLab account to your main contact at ACDH or to <acdh-tech@oeaw.ac.at>, naming the project / team you want to join. Our admins will then add you to the respective mattermost team.

##3 Accessing Mattermost

1. Go to <http://mattermost.acdh.oeaw.ac.at/> or directly to your team’s address `http://mattermost.acdh.oeaw.ac.at/{teamname}` and click on  the „GitLab“ button 
2. You will be shown the GitLab login form 
3. Login with the account chosen in step 1
4. You should be able to see the project’s workspace.

## 3 Download the mattermost stand-alone client

For ease of use we recommend downloading the mattermost client application at <https://mattermost.com/download/#mattermostApps> which is available for PC, Mac or Linux as well as for mobile devices.