The most important forms for a beginner to learn are Chen-style Old Frame No 1 (First Form) and No 2 (Cannon Fist).
A beginner should first make sure the posture of the movement is correct. Then, be sure the transition from posture to posture is correct (movement). And then learn to understand all the finer details of coiling movements from outside to inside, from big to small, staying connected from the tip of fingers to dantian (abdominal energy center). For the stances, I think students should start from higher stances and gradually go lower. YMAA has also released a video lesson on the Chen 56 demonstration form, which is a shorter form, combining both First and Cannon Fist Forms, which I find to be more encouraging for you to learn Chen-style.
There are also many other forms in Chen-style system. Four traditional forms, Old frame 1 and 2 and New frame 1 and 2. There is another competition barehand form that is newer and shorter than 56. The form is supposed to be done in 4 min. There are two competition Chen swords (old and new). There is one Chen-style broadsword form and one Spring Autumn Big Broadsword. There is a spear form and probably some double weapon forms. There are other shorter forms compiled by Master Chen Xiao Wang. Chen Zheng Lei also compiled some short barehand forms, i.e., Chen 18, 19, 38 etc.
Ease Into Martial Tai Chi
Personally, I would recommend students to study Yang-style first to experience the health and relaxation of tai chi and then add the more-challenging Chen-style as their primary tai chi martial art training. Any other styles will become easier once you have strong foundation from these two styles. And I would recommend to start with Yang-style first because it is relatively less physically demanding and is easier to learn. And cross training would be always good in the tai chi learning because they benefit from each other. The understanding of tai chi would be also more broader.
The Chen-style traditional forms offer progressive training. The first form focuses on Peng, Lu, Ji, An, or Ward Off, Rollback, Press and Push, as primary techniques and Cai, Lei, Zhou, Kao as assisting techniques. This builds our foundation physically and mentally, and is a common focus in many tai chi styles. But, in Cannon Fist, Cai, Lie, Zhou, Kao or Pull Down, Split, Elbow Strike, and Body Leaning Strike are used as the primary techniques and Peng, Lu, Ji, An are used as assisting techniques, which deepens the skill and nuance of your practice.
Old Frame and New Frame share the same principles, but the "new frame" has smaller circles, more FaJin and chin na movements and more refined hand forms. According to grandmaster Chen, Xiao Wang, "The routines devised by Chen Changxin continued uninterrupted until the seventeenth generation and my grandfather Chen Fa-ke. He went to Beijing in 1928 to teach taiji. During the several decades he was in Beijing, based on his own understanding, experience and knowledge, he added new movements onto the Old Frame, still based upon the principle of taiji, to create the New Frame branch of Chen family boxing which is widely practiced today."
Old Frame and New Frame
"In essence the Old Frame and New Frame are the same. In contrast, however, the New Frame has more explosive movements and therefore is more demanding physically. In this sense, the New Frame is considered more suitable for people who are younger and fitter. However, the latter is harder to perform well because of the complexity of the smaller spirals, and so the former is usually taught first. If you really want to strictly separate and compare the two, the smaller spirals of the New Frame are harder to execute and the internal feeling of the form takes longer to experience. If incorrectly understood, this often leads to erratic, exaggerated swaying movements, which can look very ugly.
In Chenjiagou (Chen Village, the birthplace of Chen-style), the Old Frame is used as the foundation form because it is steady and fluid, so it is easier to understand and the principle. In Chenjiagou, people have the advantage of knowing both the first routines.
To be accurate, Chen Zhoukui is the one who spread and popularized the New Frame. After the death of his father in 1957, he travelled extensively in the 1960s teaching in Shanghai, Nanjing, Zhengzhou and other cities. In the 1970s, he came back to Chenjiagou every year. So it would be more accurate to say that the New Frame was created by my grandfather, but was taught by my uncle."
Repetitive Practice Advice
"You can easily fit ten repetitions of the form in two hours. Do this every day and in 365 days, doing the form ten times every day, imagine how many repetitions you will have done. It is all a matter of determination and perseverance - if you really want it.
Repetitive practice of the form leads to complete familiarity with the movements. Over the course of time, coordination and flexibility are naturally attained throughout every move contained within a form. What you must aim for is to be able to perform every movement in a fluid and unpredictable manner, shifting without warning from slow to fast, from soft to hard, and from light to heavy."
The above is an original article by Chenhen Yang. His two DVDs, Chen Tai Chi First Form (74 postures) ISBN: 9781594397592 and Chen Tai Chi Cannon Fist (43 postures) ISBN: 9781594397608, YMAA Publication Center, Pub date April 2020 are available.