Circle to Runway???

You would come into the airport at whatever altitude ATC tells you, then make a *box* pattern using right turns around the airport, untill you are flying with the target runway on your right.

Then turn right and land on the runway

CTL approaaches are used primarily to allow an approach to a runway that has a published precision approach and then make a landing on another runway once you have descended into VFR conditions. As an example, let's say the wind is favoring runway 10 but there is an overcast and RW10 does not have a published approach. You could request an approach to RW 22 which does have a published approach and receive a clearance such as "cleared for the RW22 ILS approach. Circle to land on RW10, make right traffic".

Descent and visibility minimums are always higher for CTL approaches than for ILS or GPS approaches because of the lack of precision. I happen to have the RW10 ILS approach plate for L. Armstrong-New Orleans in front of me. For Category A and B aircraft, ILS approach minimums for that approach are 206 feet and 1/2 miles visibility. The VOR approach minimums are 360 feet and 1/2 mile. Circling minimums are 520 feet and one mile. At airports where there is significant rising terrain, circling approaches may be restricted to segments of the surrounding airspace or prohibited entirely.

I hope this helps.

Well explained by Don, in the simplest of terms you descend on the ILS/NDB etc this way if IMC you know it is safe. Once you are beneath the cloudbase and can remain to do so circle for the favoured RW