Fama-MacBeth methodology

I am an undergraduate student and I really need your help with a problem, I just hope somebody will reply me soon enough so I can finish my work.
My problem is about Fama-MacBeth methodology, that I don't really understand in all it's aspects. My teacher asked me to apply this methodology, but not as usual on portfolios, but on assets. I have 36 assets, more exactly, part of the CAC40 index which I'm supposed to use it as a proxy for the market portfolio.
My very very important problem is that I don't really understand how to form a panel in Excel (as my teacher told me) and then to introduce it in STATA and run just the cross-section regression of F-MB. the period that I've considered in my study is 2004-2017 and I don't really know how I'm supposed to apply F-MB just for 36 assets and for just 14 years. I will attach you my data that I have in EXCEL so you can see what I'm talking about. Unfortunately, I can't attach any excel format on this forum, so I will attach some PDF document. I really need your help with this, dear community

In EXCEL I've done the following computations: rolling beta, rolling returns, I've applied simple regressions for every asset with CAC40 to find the intercept and the residuals and then the standard deviation of these residuals that I thought I needed to use them in F-MB model as being Sm. In the results obtained by F-MB, the did the determination coefficient between the return of every portfolio the formed and the return of market portfolio M, but am I supposed to compute this R2 for assets instead of portfolios, but using the same formula?

The idea is that if you could help me to create that panel of data in STATA, I think I'm able to manage all the other operations to obtain the results about returns and the behavior of the market. I'd be really grateful as at this moment I'm really helpless with this situation.