As Mackenzie said, doing nothing is always worse than doing something but accidentally doing the wrong thing. Most of the time accidentally appropriating is easily forgiven as long as you correct the error and don't repeat it.
Immerse yourself in Country (the site) to get a feel for what it needs.
Use local native plants that are of significance to the local Aboriginal community (in our case, the Ngunnawal people)
Use your own designed motifs depicting local flora and fauna, provided they aren't in the style of traditional Aboriginal art
Commission an Aboriginal artist to create a mural or other artwork
Use words from the local Language- provided they have been taught by someone from that community, or have been gifted to the public domain. For example, we can use the Ngunnawal words 'Yuma' (hello), 'Yarra' (goodbye) and 'Dhjan Yimaba' (Thankyou) as they have been gifted to the community by the Ngunnawal people
Ask an Aboriginal person for clarification if you are not sure about something
Contact the United Ngunnawal Elders Council for permission to use symbols/language/stories or anything you might think will require permission (https://www.communityservices.act.gov.au/atsia/committees/ngunnawal_issues)
Use symbols or icons in the style of traditional Aboriginal art that you have made yourself or from a source where you cannot verify its origin
Use 'dot painting' motifs that you have made yourself or from a source where you cannot verify its origin
Use an artwork from an artist without acknowledging the source, or asking for permission
Depict Aboriginal culture or people in a way that is derogatory or condescending, for example using clichés or stereotypes
Tell stories from Aboriginal cultures, or the dreaming stories of native flora and fauna, without being given permission by the Aboriginal community from where the story originated
Use words from the local Language that have not been gifted to the public domain, or words that have not been taught to you by someone from that community. (For example, the Ngunnawal word for 'welcome', that has previously been used now cannot be used due to recent linguistic discoveries)