Open up your "User profile settings" by clicking on Avatar in the top right corner as shown here and then selecting the small gear icon in the top right:
In the User Profile Settings, scroll down to "Language" to select from "English" or "German"; select your "Timezone and Region" (this will affect date formats etc).
To change your password, tick the "Change password" box and type in your "Current Password" and your "New Password" (and then confirm your new password).
Click on "Save" and then close the "Accounts" tab.
NOTE: if you already have the CRM app open in another tab, remember to do a browser refresh to update the app to reflect your new settings.