How to calculate bandwidth use with SNMP and Logstash

Thank you so much for your guidance on this topic, it serve exactly my need. I followed your example and created a new .conf pipeline in my logstash pipeline folder. But I can't figure out where I should store the query_ifIndex_template.json If I store it in the pipeline folder directly, it doesn't work and crash my logstash instance :

[2021-12-30T22:25:23,339][ERROR][logstash.agent ] Failed to execute action {:action=>LogStash::PipelineAction::Create/pipeline_id:main, :exception=>"LogStash::ConfigurationError", :message=>"Expected one of [ \t\r\n], \"#\", \"input\", \"filter\", \"output\" at line 1, column 1 (byte 1)", :backtrace=>["/usr/share/logstash/logstash-core/lib/logstash/compiler.rb:32:in compile_imperative'", "org/logstash/execution/AbstractPipelineExt.java:187:ininitialize'", "org/logstash/execution/JavaBasePipelineExt.java:72:in initialize'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:47:ininitialize'", "/usr/share/logstash/logstash-core/lib/logstash/pipeline_action/create.rb:52:in execute'", "/usr/share/logstash/logstash-core/lib/logstash/agent.rb:383:inblock in converge_state'"]}

If I put the json somewhere else I have this error :

[2021-12-30T22:37:10,481][ERROR][logstash.javapipeline ][main] Pipeline error {:pipeline_id=>"main", :exception=>#<Errno::ENOENT: No such file or directory - query_ifIndex_template.json>, :backtrace=>["org/jruby/RubyIO.java:1237:in sysopen'", "org/jruby/RubyFile.java:365:ininitialize'", "org/jruby/RubyIO.java:1156:in open'", "/usr/share/logstash/vendor/bundle/jruby/2.5.0/gems/logstash-filter-elasticsearch-3.11.0/lib/logstash/filters/elasticsearch.rb:103:inregister'", "org/logstash/config/ir/compiler/AbstractFilterDelegatorExt.java:75:in register'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:232:inblock in register_plugins'", "org/jruby/RubyArray.java:1821:in each'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:231:inregister_plugins'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:590:in maybe_setup_out_plugins'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:244:instart_workers'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:189:in run'", "/usr/share/logstash/logstash-core/lib/logstash/java_pipeline.rb:141:inblock in start'"], "pipeline.sources"=>["/usr/share/logstash/pipeline/logstash.conf", "/usr/share/logstash/pipeline/snmp.conf"], :thread=>"#<Thread:0x6fe49869 run>"}