Click on Awards on the left panel and choose Manage Budgets. All the budgets you manage are listed on the page. Click on the share budget icon on the right side of the budget to be shared. Add email id of the user you want to share the budget with along with the number of points to be shared. You can also add more users to share the budget with and the respective number of points you want to share with them. You also have an option to upload the users in bulk.