Cell phone/ app version questions

Hi, I have several questions about using zoom on a cell phone as I’m having some issues.

1) I have the app installed, but I usually open zoom from a link that a Skool.com classroom (for zoom course I’m taking) has listed - so does that default to the app or the laptop/online version??

2) the issues include not being able to see everyone else on the zoom call – I can only see the one person that’s talking – which is frustrating. I also have to continually touch the button at the bottom to see the Chat- whereas on the laptop version, I can see everything all at once. Is there not a way to do this on a cell phone? 

3) when I try to react to someone’s comment (with a thumbs up or heart sign, etc.) and I tap on the message, it doesn’t bring up any sort of keyboard to do so. 
maybe it’s bc I’m on the cell phone/app vs laptop version of zoom?? 

thanks so much!!!