Open education resources (OER) and accompanying open education practices (OEP), are changing the education landscape. For educators to take full advantage of the opportunities OER offer they must engage in learning activities to facilitate the extension and adaption of their practice. This paper forms part of a larger study exploring how adult educators learn from and through their engagement with OER in the contexts of their work. Following a quantitative investigation of the learning behaviours of 521 educators around OER use, follow up interviews were conducted with 30 participants. The interviews explore in greater detail the ways knowledge is being (re)generated and used by the educators as they learn new practices with and through OER. Six broad knowledge types were identified as supporting the expansion of practice. The data suggest educators not only require multiple types of knowledge, but also must be able to move fluidly among these different types of knowledge.