If you are looking to get use to the new interface but still want to utilize the toolbars do the following to bring them back to life;
Type CUI at the command line to bring up the Customization User Interface dialog box.
Click on the Default (current) workspace and you will see in the right panel "Workspace Contents" click on the "Customize Workspace" button.
You will see back in the left panel you will be able to add check marks to items. You can click the plus symbol to expand Toolbars to check only the toolbars you want or click the check box next to Toolbars to add all toolbars.
Click the OK button in the CUI dialog box and you will now have your toolbars.
For AutoCAD Architecture and AutoCAD MEP you may not have any toolbars loaded. To load the toolbars you have to do the following:
Still within the Customize User Interface (CUI) click on the Transfer tab.
You will need to open the ACAD.CUIX by clicking on the folder icon in the right panel.
Navigate to the ACAD.CUIX by default it should be located in the C:\Users\user profile folder\AppData\Roaming\Autodesk\software folder\enu\Support.
You will now see all the toolbars listed below on the right side panel. You can expand the Toolbars and select only the ones you want to bring over or you can select them all. You will then drag and drop them to the left panel under the Toolbars section.
Once you click the APPLY button you will see the Toolbars appear on the desktop. Click the OK button to get out of the CUI dialog box.