There are many books with exercises
to relax and feel good.
These books are not written in simple language.
Here are 4 examples:
Thich Nhat Hanh:
How to relax.
Parallax Press 2015.
The anxiety toolkit:
Strategies for fine-tuning your mind and moving past your stuck points.
Tarcher Perigee 2015.
The little book of mindfulness: 10 minutes a day to less stress, more peace.
Calm: 50 mindfulness and relaxation exercises to de-stress and unwind.
Metro Books 2015.