Forced from Ver-6 to Ver-7 - Layout is all wrong, how to fix?

Hi, I have been with Ver-6 for a year,
and deliberately have resisted upgrading to later versions. I prefer the legacy classic layout.
5 days ago my Ver-6 stopped accessing my pop server, so I was forced into uninstall Ver-6 and install Ver-7, imported from backup database OK.
I don’t like the new layout, and can’t find many options to customise.
For example, current message shows in right panel with no history, just three dots. Each time I have to click on the 3 dots to expand the message conversation history.
Also, in the Inbox, the “From” column shows multiple names, the sender which is the only one that should be in he column, but also shows recipient name (me) which is confusing when sorting 100s of messages.
Is there a way to customise the layout back to some form of normality?

Suggest: menu/ settings / mail and fiddle about with the options until you are happy.
Also look at appearance and do the same. Maybe take a look at themes too.