To access a family profile e.g. a child’s profile, click on your name (top left) on the home screen. Select the profile you want to access from the dropdown menu.
Another option is to click on your name or picture from the app’s main menu, then click on the corresponding profile from the “Family Profiles” section.
To return to your profile, select it again from the dropdown menu or press the “Switch to the Main Profile” button from your profile screen.