No problem, glad to help out a fellow mapper.

I'd recommend watching tutorials on youtube, that's how I started. Aside from Profantasy's official channel I found Joe Sweeney's channel very helpful. There're a few other channels too.

Make sure the text layer is unfrozen/unlocked and click the 'Numeric Edit' button on the left tool panel. The mouse cursor should have a small box next to it, then click on the text you want to edit. This should open the 'Edit Text' window. In the 'Properties' settings you can change the font, size, and alignment.

If you want to change the text color you need the 'Edit Properties' button right above the 'Numeric Edit' button.

I put text on a separate layer, either on the 'GAME MASTER ONLY' or 'TEXT' layer. Similar to sheets, click the 'layer' button on the top bar. This opens the list with layers, the first box is to select the current active layer, the second to hide/show the layer, and the third box is to freeze the layer.

I put all secret doors and traps on the 'SECRET' layer so you have to hide that one as well for player maps.

:)

Sheet effects are turned off by default. Click on the 'sheets' button on the top bar, check 'Activate Sheet Effects', and then click the 'Apply' button.

I've been using CC3+ on various Linux computers using Wine without any problems for a couple of years now. You can use a frontend like PlayOnLinux and simply follow the install wizard.

Edit: You may have to install the Microsoft Core Fonts library if the text is unreadable.