Please assign the "Mass Assign Permissions" permission set to start using the Mass Assign Permissions app.
Along with the permission set, the following system permissions are required. Hence, assign below as well to use the MAP app/tabs.
Customize Application
Custom Permissions
View Roles and Role Hierarchy
View Setup and Configuration
Manage Profiles and Permission Sets
Assign Permission Set
The "Mass Assign Permissions" permission set contains the following permissions:
App
Mass Assign Permissions (MassAssignPerm__Mass_Assign_Permission)
Mass Assign Permissions (MassAssignPerm__Mass_Assign_Permission1)
Tab
About Mass Assign Permissions
Mass Assign Object Permissions
Mass Assign Field Permissions
Mass Assign Apex Class Permissions
Mass Assign Visualforce Page Permissions
Mass Assign Permission Sets
Mass Assign System Permissions
Apex Class
AboutPageComponentController
AppStatusTrialRenewHeaderBarCntrTest
AppStatusTrialRenewHeaderBarController
GetFLSController
MassAssignApexClassPermsnCmpntCntlerTest
MassAssignApexClassPermsnCmpntController
MassAssignObjectPermissionsController
MassAssignPagePermissionsCmpntCntrlrTest
MassAssignPagePermissionsCmpntController
MassAssignPermissionSetController
MassAssignSystemPermissionsController
PostInstallClass
SLDSDynamicLookupController
TestClass
ToolingAPIService
UninstallClass
Utility
Visualforce Page
AboutPage
GetFLS
MassAssignApexClassPermissionsPage
MassAssignObjectPermissionsPage
MassAssignPagePermissionsPage
MassAssignPermissionSet
MassAssignSystemPermissionsPage