Denied access for different roles to each other clients/leads/contacts etc

Denied access for different roles to each other clients/leads/contacts etc

hello

How to block any view/tasks/companies for different users

I have clients for 2 managers they have the same role type

I assigned companies/leads to each of them

But when they try to see All Tasks

or all leads

they can see all company clients


I would like to grant access only for owners of the lead/contact/company/task