I mean that there are no additional features to predict the time series other than the series itself (so no metadata of sorts, like hour of the day, day of week etc). As I’m trying to understand LSTM it makes sense to me to first try a simple prediction exercise using only the series itself (predict t+1 from previous  timesteps) and then improve accuracy by adding metadata to each timestep (predict t+1 from previous timestep with metadata for each timestep).