PanelView Plus and RSView Studio can be moderately complex, so in general you should begin by RTFM. There's a PDF user manual accessible via the Help menu in RSView Studio.
The first followup you should post is how you are physically going to connect the PV+400 to the MicroLogix, and what steps you have already taken in RSView Studio to configure this communication path.
If you are using RS232 to connect to both the PanelView Plus (uses RSLinx Enterprise) and the MicroLogix 1100 (uses RSLinx Classic) and you have only one RS232 port on your computer, you're probably going to run into a resource conflict or a lot of flipping back and forth between drivers.
Either use Ethernet to connect to the MicroLogix 1100, or get yourself another RS232 port. You can theoretically use RSLinx Enterprise and Classic on one serial port side-by-side, but I prefer to just use anothe RS232 port and avoid the hassle.