We’d recommend you ask for advice from a qualified packer
You can follow the manuals for your reserve and harness carefully if you like, but take particular care to ensure that the reserve is compatible with the harness. If you’re in any doubt, seek advice and help from someone who has been trained and qualified through the BHPA programme. There may be someone in your local club who can help, or you can ask a professional packer to check compatibility and install your reserve.