Everything here is from the references shown below, with a few comments in an alternate color.
The two fully charged nitrogen bottles are designed to provide only one extension of landing gear.
(1) EMER LDG GEAR Handle . . . Push in
(2) Dump Valves (OHPTS/HYD) . . . RESET
(3) Dump Valve Indication . . . Verify transition from cyan to white
(4) LANDING GEAR . . . Retract
Gulfstream GVII-G500 Airplane Flight Manual, Revision 4, August 29, 2019
Gulfstream GVII-G500 Production Aircraft Systems, Revision 3, July 15, 2019
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