Cyric

The Dan Tian requires a Dan to manifest the breath there. Getting there, you don't need the navel field, you need Xuan Guan(玄關一竅). Instead of nurturing a seedless field, look more into Wuwei.

I'd highly advise to let things manifest when it's their proper time, but in the mean time I'll do my best to explain from experience. There's a bit of confusion as some texts and schools name Huan ting(Yellow court) as the Lower Dan Tian and some that put it behind the diaphragm within the "Jade ring" and the Middle Dan Tian. Such books lead to delusion becoming even more deluded, read less, practice more. The general area of the Middle Dan tian is the Solar plexus. When Kan ascends it enters at the back between the shoulder blades, Li descends the front with a sensation in the diaphragm. The lower Dan tian is slightly below the navel. You shouldn't concentrate too hard on it. Keep Shen centered in the head and gently rest your attention at the navel. The turtle(embryonic) breath manifests there as a 'field' about the size of a fist that moves back and forth between Qi Hai and the spine at regular intervals, pulling and relaxing on Hui Yin naturally, which regulates Kan and Li to proper measure. All of this requires no intention(yi) whatsoever. When it happens, it will also continue without effort or regulation. Doing things is easy, it is not De, does not lead to Dao.

Greetings, Despite the late introductions, I have been here long, cannot even remember. I stumbled here as a seeking youth maybe some ten odd years ago. For what I have found and attained, I consider many of you my benefactors. I hope to gain some more, but also share my knowledge, to protect and guide the seeking youth of tomorrow, so they may avoid some twists and turns and begin to enjoy the scenery. Thank you for sharing your wisdom.