Step 1: Select the REGISTER module from the module navigation menu.
Step 2: Add items in the tab.
Step 3: Add another tab and add items in the tab.
Step 4: For existing order (right-click on an item and click on " Add to existing order" then click on the previous "tab name").
Step 5: To add all items to the existing order (right-click on an item and click on " Add a ll items to existing order" then click on the previous "tab name").