We live in a mobile home and have Ad Valorem Taxes and Non Ad Valorem Taxes. Do I add both together and put in Real Estate Taxes? If not, where do I put these sums?

No, don't add them together.

Ad Valorem taxes are entered under Property Taxes (Deductions & Credits >> Your Home). In TurboTax desktop, search on "property taxes - real estate" and use the "jump to..." link to go to that section. See screenshot below - click to enlarge.

Personal Property Taxes (non-ad valorem) are entered separately under Deductions & Credits >> Cars and Other Things You Own. Search on "personal property taxes" and use the "jump to..." link for this section.