I do not have a deep knowledge about Electronics, but I gained my basic knowledge from high-school and self taught after that. I need to know which software I can use to design electronic circuits with logic gates. Basically, I need to design a logic gate system (for a specific purpose) and convert that into a real circuit diagram adding electronic parts (transistors, IC, Resistors etc.) and do the simulation to see whether it works. After that I can assemble the real circuit. Is there any simple software that I can use for this? Any suggestion would be deeply appreciated.
You can use a SPICE simulator, for example LTSpice which is nice and free. These are more geared towards analog simulation, a bit awkward to use with logic, but it'll work.
For complex logic you can also use something like Xilinx ISE in schematic mode (also free). It's a FPGA design tool, but you don't have to use the FPGA bits, you can just use the logic simulator.