Sort in FOSElasticaBundle

I am using FOSElasticaBundle in my project to search on my object Player. Since I only want to search for objects with a property isactiveby value 1, I followed the documentation on the "Filter Results and Perform Query by Default" page : FriendsOfSymfony / FOSElasticaBundle / README.md

$query = new \Elastica\Query\QueryString($searchterm);
$term = new \Elastica\Filter\Term(array('isactive' => true));

$filteredQuery = new \Elastica\Query\Filtered($query, $term);
$players = $this->get('fos_elastica.finder.xxx.player')->find($filteredQuery);

My package configuration is as follows:

fos_elastica:
clients:
    default: { host: localhost, port: 9200 }
serializer:
    callback_class: FOS\ElasticaBundle\Serializer\Callback
    serializer: serializer
indexes:
    xxx:
        client: default
        types:
            player:
                mappings:
                    firstname: { boost: 3 }
                    lastname: { boost: 3 }
                serializer:
                    groups: [elastica, Default]
                persistence:
                    driver: orm
                    model: xxx\FrontendBundle\Entity\Player
                    listener: ~
                    provider: ~
                    finder: ~

Now I want to do some sorting and shorten the result with constraint and offset. How can I achieve this?

I found a solution like

$finalQuery = new \Elastica\Query($boolQuery);
$finalQuery->setSort(array('price' => array('order' => 'asc')));

But I do not have an Elastica \ Query object, and AbstractQuery does not support this method. Same thing with

$elasticaQuery->addSort($sort);

What to do? Where to read ???: //

(besides, if we are already here: what does {boost: 3} really do?)