Let's get warmed up to the idea of repurposing the dining room by removing the table setting and all but one chair. Now you have the home office you've been wanting. Use a couple of drawers in the adjacent buffet for file storage. Return chairs to table when company arrives. Easy. Done.
De-clutter. Start things off on the right foot by removing everything that you don't use. Throw away things you haven’t touched in a year, and file away important papers or items sitting in piles throughout your space. You will be able to tackle your workload much more efficiently in a clean office.