Need help on Workflow Approvers matrix on Workflow activity

[Mohammedwaseem]

we have a requirement for our custom table workflow.

3 levels of Approvals

first level= Requestor manager

second level = General manager /CE group / SE group

third approval = Leadership Group Approval

For second level approval , we have following criteria

there is Cost center field with value numeric.

if cost center = 1-100 ->then approval should trigger to CE group

if cost center = 101-200 ->then approval should trigger to SE group

if cost center = unlimited -> then approval to General manager

written below code on Workflow activity Run script.  

var cost = current.cost_center;
if (cost >= 1 && cost <= 100) {
        var userGR1 = new GlideRecord("sys_grmember");

        userGR1.get("group", current.sys_id);

        return userGR1.getUniqueValue();
		
    }

How to add approvers based on criteria using workflow activity?

I am unable to configure second level.

Please help me as i am new to servicenow.