Requeening. First, be absolutely certain that the bees to receive the new/replacement queen are "hopelessly queenless".
Hopelessly queenless is when the bees have no queen, nor any means/resources remaining, that they might produce their own replacement queen from. A situation created by removing any/all queens that may be in the hive, then waiting four or five days, so any eggs that were laid before the queen was removed, have aged enough so that the workers would be extremely unlikely to be willing or able to attempt growing the larva into queens. After the waiting period, inspect the entire hive, very thoroughly (shaking all the bees from the combs, checking for any eggs or queen cells which may have been started). If you don't shake the bees from the combs, you may overlook a queen cell tucked between the comb edge and End Bar, etc. If you see eggs, there may likely still be a queen in residence - she will need to be located and removed - and the timeline reset.
Once you are certain the hive is "hopelessly queenless", then you can install the replacement queen, in her cage, and allow the bees to get used to her and release her. Apparently, many hives will only accept an introduced replacement queen, when they have no other option.