No, you only have to perform the setup correctly once. After that, the Glowforge is linked through your Wifi network.
To get to the Dashboard from any device and operate the machine, you have to go to app.glowforge.com , log in if you haven’t already signed in to the forum (click on your name in the upper right-hand corner of the screen) and you will be able to access the Dashboard.
In order to run a job, you do have to turn on the machine.
There is a list of suggested reading here to get you started:
From a design standpoint, you can use whatever software you are comfortable with to create your artwork, as long as it can export the correct type of file so the Glowforge can read it. (That currently means either SVG, PDF, JPG or PNG files.)