All participants of a call are visibile during the call in the ALL view, either via video if the camera is turned on or via the profile picture if the camera is turned off.
You see up to 9 participants on desktop and up to 8 on mobile devices on the first page. When there are more participants you can move to the next page/s to see everyone.
All tiles are presented in alphabetical order. You can always see yourself on in the first tile of the first page.
On desktop you click on the arrow on the right hand side to move to the next page or scroll at the bottom of your screen:
On mobile devices you scroll up and down to see the different pages: