1. Configuration - Options, Display, uncheck "Tree: Press ENTER to ...".
2. Switch to tree view in any panel.
3. Click directories in a tree, TC will display their contents in another panel.
Also you can use additional trees, one or two, just choose corresponding menu item under Show - Separate Tree. Theese trees won't occupy entire panel. You may focus separate tree using mouse or Shift+Tab.
Or use the keyboard:
Ctrl+Right arrow in the left panel opens the folder under the cursor in the right panel
Ctrl+Left arrow in the right panel opens the folder under the cursor in the left panel
Ctrl+Up arrow opens the folder under the cursor in a new tab in the same panel
Ctrl+Shift+Up arrow opens the folder under the cursor in a new tab in the other panel