Setup a Workspace
Setup your project Workspace and connect with a Boomi Account
To use Boomi Console you need a project Workspace directory (per Boomi Account) where all the data is stored. I recommend using the BoomiConsole directory where you have installed the binaries and create a new directory called Workspace.
If you want to connect multiple accounts, for example for consultants who work with several customers, it is recommended naming each workspace after the account and organising all workspaces in the same BoomiConsole root folder.
Three Steps
Collect information: Boomi Account Connection
Open a console window and navigate to your Workspace.
Initialize and connect your Workspace
Use the connect batch-file to start the guided process. Use the Console - not PowerShell!

Connect is a batch file located in the Boomi Console binary directory. It will initialize the Workspace (if not yet done) and it'll guide you through the Boomi Account connection process.
...\Workspace> %bc_dir%\connect

Linux or Max users must run the two steps manually:
Google Drive spoiler!
DO NOT USE Google Drive to store your Workspace!
Google Drive is not really compatible with Windows File System, and I encountered serious and strange issues. For example: I tried to create a directory and I got the message "already exists" and when I tried to navigate to there the message was "cannot find directory":
md "g:\...\bc\Out" -> A subdirectory or file g:\...\bc\Out already exists.
cd "g:\...\bc\Out" -> The system cannot find the path specified.