How to search in my index?

After removng ELK, I migrated to opensearch.
Now I have the following packages:
logstash-oss , opensearch and opensearch-dashboards
I get my data in input such as:

input {
         udp {

It’s work and even I can my information in stdout {} I don’t have problem with them.
I have the following filter for jasonize my information:

filter {
    dissect {
        mapping => {
            "message" => "%{timestamp} %{+timestamp} %{+timestamp} %{year} %{priority} %{sourceIP} %{host} %{msg}"
        remove_field => ["message"]
    kv {
        source => "msg"
        remove_field => ["msg"]

And with stdout { } I can see jsonized my information.
With output I send my information to opensearch:

output {
          opensearch {
                 host => [""]
                 user => "admin"
                 password => "mypasswd"
                 ssl => false
                 ssl_certificate_verification => false
                 index => "logstash-logs-%{+YYYY.MM.dd}"

When I see index management, I can see name of my index, But When I open discover I only see 2 index pattern (default sample) and I don’t see my pattern.
How can I search in my index?

You have to define Index Pattern