i am very new to bioconductor and R, so have this in mind when answering the question. for my experiment i first have to run an in silico analysis on several gene expression datas from GEO and ArrayExpress. i wanna check the biologically meaningful differential expression between samples ( which are gene expressions from 3 different cell types) and then to visualize the data more explicitly i wanna do gene enrichment and also interpret it as a pathway. how can i do so ??? can someone please walk me through the steps and softwares or packages i would need to do this in silico analysis ?