Hi! The button should be there, but it seems like your monitor size is the problem! After pressing the generate gerber button, the window has popped up, but the window is a set size and your monitor size is not letting you see it. Try zooming out the webpage by pressing CTRL & (+/-) or CRTL and scroll the mouse wheel. That will zoom in and out the webpage in the browser and allow you to access that button. Also I see you have some downlaoded files on the bottom, you could press the little X on the right and that bar will go away and you might see the gerber button. Here is a gif :  <br> On another note, if you really want to succeed in the college competition, the layout could be better. Let's start with placement and rotation. You could help yourself a lot if you just rotated some components and placed them closer to what need to be connected together.You could rotate R2 and have the pins connect with shorter traces and move it closer to the DIP40 pin. The crystal part is a bit messed up. Are the caps C1 and C2 load capacitor for the crystal X1? Why have you got them so far away from it and snaked the traces all around? Looking at the small image of your gerber, I can see thet U3 is connecting to the top part of the big DIP chip, you could put that one up top and have neater traces that don't go over the whole board. Also, no bulk capacitor or any decoupling caps are on your board. Have some 10-100uF electrolytic capacitor on the input of the board for bulk capacitance and a small 0.1uF(100nF) on the power pins of the microcntroller. Also can put one cap for the reset pin. I don't have a schematic for your project, but just had a little go at replicating what components you have there and give you an idea of how you could improve it! You could also use GND planes for connecting all the GND connections with copper areas with GND nets on the top and bottom players.  Hope this helps you to get this done and hope you have success in your competition!