As put in the comments, you need a 3D rendering tool - not Inkscape - and you probably need to learn more about drawing and perspective. No offense intended - but the "3Dish" effect of the HTML5 logo is very far of what will be obtained in a tool that really takes 3D into account - you should really strengthen a little bit of your knowledge in this area specially if you need to deal with it professionally.
Blender3D is such a 3D tool - for realistic looking 3D effects - it will give you nothing close to the HTML5 logo level of abstraction from 3D. That one has been created in a vector tool, taking care to emulate the 3D "feeling" of the surface and faking the shadows.
If you simply want to adjust the perspective of some text to a rotated 3D lat area, like the cover of a book, or stamp text on the sides of a cube: inkscape could do that but it once: what is needed is a free perspective transform. Inkscape even allows you to specify your 2D transform matrix, but it does not allow you to visually match your transformed object to the target. You can do that in GIMP - it's perspective tool is cool for that, and easy to use - but it is a raster based tool, so it might not fit you. (Maybe you can load your art as separate layers in GIMP, use the perspective tool there to check the needed transformation matrix coefficients, and type those back in inkscape (
Matrix tab). You'd still have to manually apply shadding, clipping text at the edges of a "cube", and transform both sides indepently, and so on.
As a rule of thumb: this kind of stuff is either drawn from scratch, by someone who grasps the fundamentals of perspective and 3D drawing - or done in a real 3D program, like Blender.