Kotlin, layout isn't working correctly

Question

Dear Community

My Composables are overlapped and I can't do anything about it. Can someone help me? First, there should be

the toolbar, then
list view
message input on the very bottom of the Activity and when I click on it, the keyboard shouldn't overlapping it.

Can someone help me please?
Thank you so much and have a nice day.

https://code.sololearn.com/cLlgz3A5zqmH/?ref=app