If you choose the avatar icon to the right of the magnifying glass, a small dialog appears. Under Settings you can make personal settings in the cloud. You will also be shown some personal information, such as your email address and storage space used.
You can deposit a personal profile picture by clicking on the up arrow (the picture will be searched on your computer). If you select the folder icon, you can select a picture that is already in the cloud.
You can also change the language of the Nextcloud.
The Activity app logs events in your cloud area. Some of these activities are reported to the user via email, others are only displayed in the cloud ("stream") when the Activity app is selected. Each user can set this individually by selecting "Advanced Settings" from the menu on the left. The picture on the right shows the default settings for the individual events.