Ideally, this would be done by using a copy of the current input.php, and adding step-by-step popup jquery tooltips to show how to walk through a scenario. For instance, you load a popup modal that states the following scenario "A couple is 40, and is aiming for 10 more years of savings. They save $10,000/yr in a 401k, and $11,000 in an IRA. Their expected SS is $____. Their spending is $_____." Each step of the way, it will show the user what to enter and where.
This should be modelled for several scenarios that all end up using the different things cFIREsim has to offer. ie: A scenario where someone is paying for kids college down the road, a scenario where someone lowers expenses half-way through the sim, a scenario where they use variable spending, etc.