Firstly, you'll need to ensure that the local server is running - there should be a green dot at the bottom of the BRE screen if it is. Or else the dot could be under the show hidden icons button highlighted in the screenshot:
If it's not there, from the Start menu, select LAE Server and run it.
Once the local server is running, check in Tools > Preferences > Server Farms to see if you have any server farms set up already. If there is not, then you'll need to configure one.
HOW TO SETUP A SERVER FARM
In the BRE toolbar, click on Tools > Preferences > Server Farms.
Then click on the "New" icon and name it something like "LocalDesktop".
Once it's created, select it and click on "Edit Farm".
Click on the "New" icon and use the following settings to configure it:
name => doesn't matter (example: LocalDesktop)
host => localhost
port => 7721
Once it's setup, you'll need to ensure that you have your server farm selected from the drop down menu in BRE and click the connect button (the icon with the green tick) per the screenshot below.
Also, please be aware that you may lose other settings such as search path, auto save frequency, etc.