Anchors Chain Issue

Hello! I am having problem in my Arabic based Sindhi Font. I am wondering how to (1) setup Anchors? (2) How to place them in Open Type Designer?
I am having trouble, every time I place them properly, but they are not working. I find out Chain on Anchor is not showing. Anyone please help how to fix this. Thanks

You need to use the specific anchor in an OpenType layout feature, as shown here for the below-arab anchor:
mark.png