From 1-6 weeks post, I pour it in my hand and slap it in there. I wash my hair in halves, so I put a big old handful on each half, smooth it down the length, and I add a little bit more on the ends. I don't comb it through, because to me, that's unnecessary manipulation. The heat melts it, so it gets to all the strands anyway.
From 6-10 weeks post, I still wash in halves, so the procedure is pretty much the same. Only difference is I part the halves into smaller sections (4 on each side) with my fingers, and smooth on the conditioner from root to tip.
From 10 weeks post+, I apply DC just like relaxer. I wash my hair in fourths, so I take one section down, use the pointed end of a coloring brush to part it into a smaller section, and then use the brush to smooth DC onto the new growth. I do that to my whole head, and then I go back to apply conditioner to the length and ends.
The last way takes the most time and uses the most product, but my new growth really benefits from the special attention and care. Hth!