Fetch data of 2 relational Custom Post in WordPress

I am using Pods plugin in WordPress. I am new user of this plugin. I have 3 Custom post type. Tasks, Teams and Volunteers. I can fetch Volunteers using this code get_post_meta($_POST[q], 'volunteers', false);. I would like to make relation of Volunteers with Tasks.

I need to fetch how many Tasks are assigned to a Volunteer. How can I fetch this ?

My database structure is like below.