Karela, never be afraid to post honest questions to the forum; that's what it's here for. It's great that you've decided to get into Scribus more. (It's also good that you're putting a new post in for each question rather than "lumping them together" into one.)
As for your question, there are two different ways to do what you want.
The first way is nasty and probably an "undocumented feature" of the UI and so is probably best avoided but I'll tell you anyway.
Scribus doesn't normally allow you to change the colour of grouped objects, it greys out the Colours tab of the Properties Palette. However, and here's the nasty sneaky bit, if you create a temporary shape and select it (or you can select an existing object that can be given a colour), then go to the Colours tab, then select the group, you can now change the colour of everything in the group. I've a feeling that this "feature" won't be available in future versions if the developers spot it so it's probably best to get used to doing it the right way.
And the right way, in your case with outlined text, would be simply to select the grouped outlined text, right-click and choose "Ungroup", then - while all of the text outlines are selected - choose menu "Item -> Combine Polygons". The text is now one shape which can then be selected and coloured as you wish. (Or you can change the colour of each letter individually without combining the polygons if that's what you want.)
And then what you can do - and this is optional - is choose "Edit -> Colours", select the colour you're using for your text, press "Duplicate" and give the new colour a name - e.g. "Logo Text Colour" and press OK. Then OK the Colours dialog. If you later need to change the colour of the logo text all you need to do is go back to the Colours dialog and change the settings of this new colour to whatever you want without changing anything else.
I hope some of this helps.