How can I insert logic units by their part numbers while drawing block diagram.

Resistors and capacitors are not supported by Quartus II because in he FPGA you can only build a pure digital circuit with no analogue components. These components should be placed externally of the FPGA. About the decoders try to browse the FPGA tree library and search for the patrt numbers. Otherwise you may directly insert the part number in the window where you can read the label "Name" and search for an automatic match with the Altera library.