Binding is a general concept of SV through which you can tie any module (say assertions/coverage) to the DUT interface of your interest.
If your covergroup class is defined in a module, then you can bind the coverage module to the module/inst of interest in the design.
Let us say coverage module is cov, module to which coverage needs to be binded is top
Syntax is something like this:
bind top cov cov1(.*);
This can also be done on per instance basis(instead of module).
bind top.inst1 cov cov2(.*);
You may need to do the connections on the naming basis if required. Refer SV LRM to know more about binding.