The cheapest graphics card you can play it on is an NVIDIA GeForce 6100. In terms of game file size, you will need at least 100 MB of free disk space available. stepbystep system requirements state that you will need at least 512 MB of RAM. An Intel Pentium 4 2.00GHz CPU is required at a minimum to run stepbystep.
stepbystep will run on PC system with Windows 7 or newer and upwards. Additionally it has a Linux version.