So far the circuit boards we've designed and layed out have been fairly straightforward: take a chip, connect the inputs and outputs to appropriate connector pins, add a few bypass capacitors, and we're done. This has provided useful practice in PCB layout, but hasn't really required much design. Now that we're proficient in layout, we can undertake more complex designs.
However, a more complex design means a less deterministic design process. Previously the chip to be used had already been selected, the chip can only be connected one way, and there are no component values to determine. For this week's exercise, you will have to choose the chip, as well as additional components whose values must be calculated. The connections required will be more complex, and there will be ample opportunity for incorrect connections. In addition to choosing your chip and creating a design around it, you must order your components, wait for them to arive, lay out your board, fabricate it, assemble and test it, and if it doesn't work, find and fix the problem, possibly requiring another round of design, order, wait, layout, assemble.
In spite of the high level of skill you have achieved at this point, it is unlikely you will be able to do all of this in one week (or even two). So this week's exercise is really an exercise that will start this week, but will continue off and on for several weeks. To assure that it does continue, rather than continue to be put off, a due date earlier than the end of the semester has been set, specifically, the first week of April.
As mentioned, the focus of this exercise is design, and since, as also mentioned, this will be a lengthy process, design will be the entirety of this exercise. I.e. there will be no other hardware or software to play with. What you do in the lab is entirely up to you. If you want to layout your final design right away, order all the parts, and only go to the lab to assemble your circuit, which will work the first time and require no further lab time to debug, that's OK. If on the other hand you want to order some sample parts, take them to the lab and experiment with them, only then beginning your design in earnest, that's OK too.