How do I push in the locking tabs?

Once the connector is fully pushed in and cannot be pulled out, then the locking tab will be able to be pushed in. You can try wiggling the connector and tab up and down or try pushing down on the tab while pushing it in. Some require a bit more effort than others as there are always slight variables in the connectors and mating connections.

Sometimes dirt and debris can prevent the locking tabs from being pushed in, so please make sure it is clean and try again.

You can also try pushing the bracket on further as it could be just ever so slightly protruding and making it harder to push the locking tab on.

Any damages during installation are not covered by warranty so please take your time and be careful. It is recommended to consult a professional if you have troubles.