Congratulations - you certainly picked one of the most beneficial areas for lean thinking! But it is also one of the most challenging ones.
But why do you want to apply lean to your R&D or innovation creation process? Typically the answers range from: "We are using it in manufacturing" to "We heard our competitors is doing it" - they are good answers but I like to drill deeper by asking: What is your biggest problem in R&D? Now I am likely to get answers like: "We cannot keep up", "every new product is late" or "we seem to have no idea what the customer wants".
If you have problems like that, chances for a successful R&D initiative are very good. But wait - we are not ready for the value stream mapping yet.
Once you understand the "why", I suggest a SWOT analysis. SWOT stands for Strengths, Weaknesses, Opportunities and Threats. I have seen companies throw good stuff they were doing out because it was not written in a book about lean product development.
The SWOT results give you a pretty good idea why you have some fundamental problems and where your gaps are. Now is the time to get an education. And do not just read one book, go to one conference or talk to one consultant. Start by educating your lean leaders but do not hesitate to educate your whole organization. Education is the first step in getting the people engaged who do the actual work. The secret about the education is to learn principles first, not the tools.
After the education you will be surprised how easy it is to engage the people who do the actual work around the real problems. Once the biggest problems are identified, then you may think about teaching your folks about problem solving, maybe the A3 process. On the job problem solving is the best education for your people on the way to a successful and sustainable lean culture.