tuned in

When one has a radio and wishes to listen to a particular station, one adjusts the frequency that the radio is tuned to, until it is tuned to the frequency that the radio station is broadcasting on.

In a psychic sense, tuning in is similar: there are a great range of frequencies, including within any one ‘level’ (etheric, astral, etc), and the act of tuning in is making sure one is focused where one wishes to be focused.

To use another analogy, it is a little like the change of focus of your eyes when you decide to look at a particular object which is closer or further away than you had been looking previously.