As you appear to have the ability to access the Internet, I would first suggest that you use a keyword search on a popular search engine (e.g. Google or Bing) to find lots of great articles and methods for free. Learning how to research a question is one of the most useful skills you can learn. The time you put into researching a question and learning about what is already known will prove valuable.
When developing a method of analysis by HPLC for sugars such as rhamnose, we first need to establish what the sugar is in (the matrix). Is is a clinical sample, pure standard etc. Also, what other compounds are present with the sugar? Sample prep may be needed before you use HPLC. You did not provide any information in this regard so suggesting a specific method for your sample is not possible. We can offer some generalizations though. If it is a clean, pure sample, then a C18 column would not be the most appropriate column choice. An amino (NH2) column would be easier and quicker. A simple isocratic mix of water and ACN will usually work well on an amino column coupled to RID. Please make sure to chose a ratio which provides good k' prime values. I have seen many examples of published reports where the scientists had no experience with HPLC and eluted it at the void volume. If higher sensitivity is needed or their are interfering compounds present, then a gradient method coupled to ELSD, CAD or even MS could be used.
Check ICUMSA (International Commission for Uniform Methods of Sugar Analysis) for simple sugars using an RID. But it depends on your sample matrix and interferences.