Login to your site as admin.
Go to Dashboard->Extened concrete5->Add Functionality and click install button near the Login Dialog icon.
For placing Login Dialog block do the following things.
Click Add Content to The Page button on Dashboard
Scroll down a little bit.
In Other section of Blocks drag User Login Dialog icon and drop it on your page.
"Login/Register" in single line
To display Welcome message in single line do the following things:
1. Login to youre site.
2. Enter to edit mode by clicking Pencil icon in Dashboard
3. Left click on Login Dialog block and select Design and Appearance menu
4. Click on Custom CSS classes Icon. Edit window will appear
5. In User Classes textbox type "in-line" (without quotes) and click Save.
6. Here you can also change font size by typing "font-16", "font-14", "font-12" an so on
And don't forget to publish youre changes
Block have three parameters only :