If you are willing to learn brush calligraphy, I can give you some advice.
First, it's paper. If you are a beginner, you can use tassel paper. I think the pen should be the most important. If you want to buy a brush, I suggest you find this article and read "Top Ten Brush Brands in China (with Brush Selection and Maintenance Methods)". This paper introduces the selection and maintenance methods of brushes in detail. If you don't know how to choose a copybook, you can refer to this article "How to choose a brush copybook for beginners of calligraphy (with the names of 46 classic calligraphy introductory copybooks)", hoping to help you.