If you want to manifest things into your life first you have to imagine and feel how it feels to have the things or things you want.
Then visualize and meditate on how your life is with the things you wish to manifest. What does it look like? What does it smell like what kinds of emotions would you have if you had the thing you wish to manifest right now?
Then after doing this believe that what it is you are manifesting is with you right now. That's how the master manifesters work.
If you want help with manifesting money or manifesting health. Then check this awesome YouTube channel out @lawsofvibrations and go to the 8 hour affirmation video programs which of course are FREE. If the adverts get on your nerves you can always look to get an MP3 recording in the video description. Read the instructions before you start your affirmation journey.