lmFit - fit expression to a linear model for each gene and calculate the residual error
eBayes - calculate the likelihood that a residual error would be seen by chance
topTable -  produce a table of 10 most differentially expressed genes

References

http://www.bioconductor.org/packages/devel/bioc/vignettes/limma/inst/doc/usersguide.pdf

https://bioconductor.org/packages/release/bioc/html/limma.html