I'm very sorry you feel that way.
Unfortunately "I can't add statements to an item or a property" is not a
description of an issue anybody can help you with.
https://www.mediawiki.org/wiki/How_to_report_a_bug might give guidance how
to ask for help.
The other issue you mentioned contains an actual PHP error message saying
"Constant WB_NS_PROPERTY_TALK already defined in LocalSettings.php". You
should check where this constant is defined a second time. Usually you do
not need the "define( … )" lines and can rely on the defaults that come
with the Wikibase extension, so it might help to simply remove these lines
from your LocalSettings.php.
I hope that helps at least a little bit.
Best
Thiemo