pecl install https://packages.couchbase.com/clients/php/couchbase-3.0.3.tgz
$connectionString = "couchbase://localhost";
$options = new \Couchbase\ClusterOptions();
$options->credentials("Administrator", "password");
$cluster = new \Couchbase\Cluster($connectionString, $options);
// get a bucket reference
$bucket = $cluster->bucket(<BUCKET NAME>);
// get a collection reference
$collection = $bucket->defaultCollection();
// or for named collection
$collection = $bucket->scope("myapp")->collection("my-collection");