ok the cola from what I know is the tippy top of your planty when she goes into flowering she'll develope a bunch of hairs at the top which will produce flowers (buds). Nodes are seen in this pic; the little hairs are at the node intersection. A node is the intersection of a branch and the main stem. That is the best way for me to explain it. think of a node as her armpit with the little hairs protruding from it