...
On your Jira Cloud site, navigate your Project settings or Project settings > Apps for team-managed projects.
On the left menu, choose Issue Matrix configuration.
On the Issue Matrices page, click the Add Matrix button.
Choose the type of the Issue Matrix from the list: Sub-tasks, Issue Links, Epic, JQL, or Similar.
Context: On the Add Matrix page, configure the context of the Issue Matrix: choose the projects and the issue types for each project where the Issue Matrix panel will be shown.
Learn more about project linkingType: In the Type section, choose the issue types shown in your Issue Matrix.
Data > Columns: Configure the information columns (custom fields, columns width, their widthcolumns headers, and headersaggregations) the Issue Matrix will show. The columns you can choose between are custom fields from your Jira Cloud instance.
Data > Results: (not applicable to the Similar Matrix type) Choose Select the maximum number of issues that to be displayed in the Issue Matrix panel can show. By default, all available results are displayedand set the number of results per page.
Data > Categories: (Optional) Configure issue categories to organize and highlight specific issues more easily using colors.
Sort By: For the Sub-task, Issue Links, and Epic Issue matrices, you can set a default sort order for the issues displayed in the Issue Matrix panel. You can choose one or more columns as a default sorting criteria among the sortable custom field list.
For JQL matrices, sorting can be achieved using sort clauses in the JQL query.Preview: Enter an issue key in the Preview area to see how the matrix panel will appear in this issue.
Save the configuration.
...