I had carryover home office from 2016, 2017 another loss and unable to claim my 2016 or 2017 home office expense. Can I claim anywhere else? Will I lose 2016 office exp?

No, your unused Home Office Expenses will continue to be carried forward until you have income to offset the expense.

Where on the program 2018 Home and Business does the program prompt you to enter a carry over?  2017 was not completed with Turbotax?