Download an older (pre version 10.0) version of altera quartus. You can pick the oldest one you can find.
Fire it up
File -> new schematic
File -> save
Double click on the drawing area to bring up library. Simp,y type things like nand2 , 74138 , input , output , nor4 and so on, place , connect wires. Doubleclick io na,es to change them. When happy -> save
File -> add new to project -> vector waveform file.
Now, at the top menu bar there are two arrows (right pointing triangles like you would start playing music. The left one compiles, the right one fires the simulator. After a change in schematic you need to compile. Just click the left arrow and wait for comp,etion.
After a first compile : in the waveform editor , left panel right-click and select import nodes.
A panel opens. Simp,y click the button 'list' and throw them all in the right panel (or the ones you want to see)
Then simp,y draw waveforms. Right click a signal to alter it.
This software is very easy to learn.
Big advantage is that, later on, you can start designing logic also with verilog or vhdl , drop that in you system and wire it up as well. And ultimately you can spit out the config file to load in an FPGA or CPLD.
It has a library with almost any ttl 74xx series out there as well as many gates that don't exist. If you need a 7 input or gate simp,y place an OR7
There are wizards to create all kinds of special functions like ram and rom , clock generators , arithmetic units and much much more.
The software is free and exists for both windows and linux, so you can't complain there.
The download is large... This is, after all, a professional tool used by logic designers to develop multimillion gate FPGA designs.