Creative Commons says it best: "Creative Commons licenses are designed for ease of use. Users can see in a transparent manner how your work is available for reuse. Things can become complicated however if you want to combine two Creative Commons licensed works, for example when making a collage or remixes of music. Not all licenses are in fact to compatible."

How do you know if you can combine parts or all of multiple CC licensed works?  First, identify which license each work has, then use the handy CC license compatibility chart available from Creative Commons. 

There are many different platforms that you can use to remix your own OER.  Here is technical information on how to author books on three of the most popular.