I don't understand how formatting works

I have a few styles, like table contents, that don’t apply their style. My table content is set to be left but even if I try to apply it, it doesn’t change what is already there. I need to change all table content to be left. What is the use of format then ?

Plus, when I copy text from a power point, it changes all the styles in my writer. Even if I undo, I have to close and re-open the writer so I lose all I have done since the last save

Whenever you apply formatting directly (e.g., via toolbar or the menu), it overrides the pre-defined formatting.

Try clearing the format and then reapplying your pre-defined style. More info in this Q&A.

As for pasting, try Ctrl + Shift + V and select Unformatted text. More here.

I hope this helps.

If you have applied a direct format on the cells, this have priority over the style, try cleaning direct formatting with Ctrl+M (Menu/Format/Clear direct formatting).

In relation to when pasting from PP, there is the Paste-special Shift+Ctrl+V (Menu/Edit/Paste special) with several options to try.

Thanks alot guys