Hello. I am completely new to DESeq2 and also R. I have reads data in the form an Excel sheet having where one column has read counts, another different sample groups and one column has species information.

I don't know if I need to transform the data into another format or something else. I would appreciate if someone could point me in the right direction i.e., tutorial, beginners guide, etc.

Thanks.

Please provide an example of that sheet (at best after reading into R and then shared via dput()) if you are seeking help. In general the vignette covers all necessary DESeq2 knowledge and I suggest to start with that: http://bioconductor.org/packages/devel/bioc/vignettes/DESeq2/inst/doc/DESeq2.html

Note that this support site here is for technical problems and bug reports of the Bioc packages For general bioinformatics help please consider using something like biostars.org as each time you post here a mail goes to the developer of the package whose expertise is usually not required for these simple non-technical problems.