I want to hide some elements appearing in posts of a Twenty Eleven based site : "posted in ... date" and "categories names". It seems that I have to create a Child Theme, and for that, I have to create a directory in the ftp where is installed wordpress (like in this useful video). Unfortunately, I don't have access to the ftp codes, I'm just workong into the wp dashboard. There is an optional method to create a Child Theme directly into the Dashboard/Appearance/Editor?
If not, someone knows a theme offering templates where I can have that posts elements hidden by default?