The bracket is all that retains the injectors - however, you must disconnect the injector fuel lines to slip the bracket off. You use two wrenches, one for the fuel line compression fitting, and another on the injector directly below, to keep it from turning. Best is to place the wrenches so the handles form a small angle to each other. Then grasp both and squeeze to loosen the compression nut. Then use only the wrench on the nut to remove the line. Once the injectors are out, you may have to carefully cut the old, hardened seals to get them off. The new ones should pop on easily.
I also found it best to remove both ends of the injector lines - at the fuel distributor too. Take a picture if necessary to get the routing right on reassembly.
'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7