My therapist said to me once. “At first your mind is like a little puppy, pulling on the lead excited to be in its new space, unpredictable. Just gently tug on the lead to bring it back in beside you. After a lot of walking and some time your puppy will stray less and less and begin to walk beside you”

That really helped me with my busy thoughts. It became not such a big deal that I had no control over my thoughts. Just gently bring them back to your surroundings and inner self