How to query solr server from php in Drupal 8

How do you query solr server from php in Drupal 8? I have installed search_api, search_api_solr and search_api_attachments. Also have Solr v.8.4.0 installed. I installed php SolrClient for Centos 7 following this guidance: https://stackoverflow.com/questions/22959330/fatal-error-class-solrclient-not-found , but I still get “Class ‘SolrClient’ not found” every time I run new SolrClient($options); I have located documentation on querying…

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