A multilayer PCB is the perfect solution for prototyping a high density and complex circuitry. And for a satisfied and error-free designing of a multilayer PCB, it is best to take advantage of the multilayer pool and tools offered by Eagle software.
A complete schematic is the foundation of the designing a PCB therefore, start with creating a schematic. From the file menu, name the project and open schematic editor window. There, using tools from the toolbar make the exact replica of your paper schematic by dropping components on the working space. Rotate and move components to make a clear to read schematic drawing. With done with this step, cross-check every component and make sure nothing is left like reference designator, value, and part number if necessary. Add net to every pin of the component and make correct connections.
The next is working on the layout which can be done with either of two ways. If you already have the shape of the board, layers, and position decided for the component, then draw the dimension of the PCB and arrange board by placing components and via on it. Then generate the netlist from schematic, upload into the board and then route the nets. Eagle software gives its user the facility to choose appropriate grid for designing, seeing each layer of the PCB like the original one overlapping each other and variety of routing options. This ease PCB designing which is one click away. You can on or off any layer using layer setting button to route each layer separately or as per requirement. The other option is making use of multilayer pool for PCB composition by allowing the Eagle software to auto-create the PCB. Then cross check all the layers, components, text and dimensions. Finally, use the design check rule option to final board layout and then finishing touch to the PCB.
Generate Gerber files from the file browser option. Review it along with remaining necessary files for the manufacturing process. Submit these files and order to a PCB fabrication house. Eagle software design guide the designer at every step and make sure multilayer PCB designing gets successful.