First choose a location which would be the ideal setting that makes you feel calm and relaxed.
Whether it be a forest, riverside, mountain top, meadow, log cabin in the woods or whatever else works for you. You can use a travel magazine for inspiration.
(Note: don’t choose a place where you have been before as that may have memories attached to them which will take you down another pathway).
Next, use your senses: what can I see, (objects, colours, and textures), what can I hear, what can I touch, smell and taste. Initially you may only be able to hold the image for 15 seconds but that is a good start. Each day as you practice, you may find you are adding more detail and that allows you to stay in your calm place for longer and longer periods.
May peace be with you.