How to interpret the target bar chart?

The target bar chart represents the Normalized Relative Quantities (NRQ) or the Calibrated Normalized Relative Quantities (CNRQ) values for all samples for a specific target.
By default qbase+ expresses the results as fold changes relative to the average expression (NRQ) across all samples for that gene.

If you want to make your results relative to a control or control group, you should set the target scaling correspondingly (in the Calculation Parameters window). This will make the relative expression for you control (group) 1, and the results for your other samples are than expressed as the fold change compared to your control (group).