Manifest, adjective: Clear or obvious to the eye or mind.
Manifest, verb: To show something clearly, through signs or actions.
Manifestation is having complete clarity of your direction, and aligning your thoughts and actions with it.
Does it work? In my experience, yes. Mumbo jumbo aside, there a logical reason why... Your brain is very good at picking out what it finds relevant - and you decide what's relevant to you.
It's easy to spot an orange car if you're always thinking about an orange car. It's easy to spot opportunities if you're always thinking about opportunities.
If you flick through a document very quickly, it isn't possible to absorb all of the information - but your brain will jump from word to word picking out what is relevant to you.
The same goes in day-to-day life, your brain picks up the breadcrumbs of what is relevant to you.
So, how to do it: Establish your direction, making your goals crystal clear, and align your thoughts with that direction.
You can add clarity by creating a "vision board" with your goals, and you can keep them at the forefront of your mind by writing these goals down every morning as part of a journaling routine.
You must, must, must take positive action on these goals. They will not just "come to you".
And my final thought is don't get too hung up on these goals, at times they may be conflicting, they may not be serving you, or it may not be the right time.
Have patience, and know when to cut ties - but never allow not achieving a goal to let you drop the process entirely.