Brush calligraphy:
Learn from Liu Gongquan first, and Liu Ti is the easiest to learn form and get quick results. If you post it every day, you can basically get started in 3 months.
Then you can learn from Yan Zhenqing and imitate his charm, followed by Ouyang Xiu and learn the shoulder frame structure.
After writing a paragraph in regular script, you can dabble in other regular scripts: Wang Xizhi and Huang Tingjian; Cursive Zhang Xu, Huai Su; Li Shuqin Bailey, Cao Quanbei and so on.
Of course, it doesn't matter if you don't follow this order. You can enter the room from any kind of book.
If it is a pen, you can learn from Pang Zhonghua, Sima Yan and others.
In fact, my personal experience is that if you write the brush words well, then the pen words will naturally be a cinch.
(odin267)