@Llopis I see that you are adding comments like "did you read the manual, did you visit bioconductor".
1. First of all, in both cases I give the question & the answer.
2. I think these kind of question do not have an easy googlable detailed answer.
3. If you look at stackoverflow, most popular questions are quite simple to solve, nevertheless they are a source of traffic and have excellent answers you cannot find anywhere else.
4. Other people (see above) seem to agree that it is good to have those type of questions which will end up in faq.