It is not recommended that you handle your own split system air conditioner installation. These units should be installed by a professional as they often involve cabling, electricity, and safety switches, which should be properly installed for optimal safety, correct operations and to ensure the warranty is maintained. While DIY is tempting, the peace of mind that comes with certification, licenses and an understanding of things like copper piping, safety switches, and refrigerant is only achievable when handled by professionals.
The savings you may achieve by installing your own split system will likely turn into costs in the long term if you need extra servicing or a re-install, plus any costs associated with the voiding of your warranty. An installation this is undertaken by a trained and licensed professional ensures that the job is done by someone knowledgeable in all areas of air conditioning installation, servicing, and maintenance.