You need to establish first which, if any, of the New Approach Directives or older Global Approach Directives applies to your product. CE marking only applies to products within the scope of these Directives. It should not be applied to products if they are outside the scope of the Directives.
The European Commission's "Blue Guide" (Guide to the Implementation of Directives Based on the New Approach and Global Approach) lists Directives where the CE Marking will be applicable. It is available for download from the Commission website.