How to guide new users?

I agree with @wavehopper, you should let them jump straight into the app as this is what they expect. There are a few other options you didn't mention in your post:

• Give the user a lot of demo data so they can get familiar, then when the user is ready they can delete all this demo data and start for themselves.
• Give a live demo trough a video call (although mostly done in more high priced products).
• Add a live support chat that contains a special message for new users that you are there to answer any questions.
• Create a good FAQ so the user can search the question specific, refer to this.
• Combine above with a tooltip.

Besides these options I do always think that this starts with good UX so the application explains itself. You could try to not explain anything, and record the users screen using Hotjar e.g. You will then see where the most questions rise. Or make your friends use it and record them as they do it, make them talk out loud what they think.

Also make sure to do some kind off follow up like a weekly email containing tips for new users!

Good luck! Hope it helps a little. theLifeBoard looks like a fun product to work on :)

I have done number 2 point for onboarding and number 1 for quickly getting users to use your product

we have split our dashboard so that above the fold are simply buttons to let them do what they came to do on dashboard which is providing immediate value, then there is a youtube video embedded below you can watch it to understand how our product works

I would let them jump straight into the app, but have some example goals pre-set up for everyone - that they can easily overwrite. You already have them in your demo. Maybe with some extra text saying "please amend me" (or something like that).
Have links to your demo or slideshow of course.

By the way - I find part of your tag line quite difficult to parse/understand: "achieve your goals creating habits". It's odd phrasing to me as a native English speaker. Does it paraphrase to "achieve your goals by creating habits" or "achieve your goal-creating habits"? These are two different meanings. Just mentioning it, as you don't want people getting stuck wondering.