Accounting for rental arbitrage isn't too different from that of a traditional rental property. However, since you do not own the property, the two major differences in this setup are:
You will have a lease payment instead of a mortgage payment
You can not claim a depreciation expense on the property since you do not own it. Any assets you put inside the property (furniture, etc.) will still be depreciated
Fortunately your lease payments are tax deductible as a business expense. To categorize lease payments, consider adding a top-level account to your Chart of Accounts to attribute these payments to each month.
To update your chart of accounts, open the right-side menu (3 horizontal lines next to your name in the upper right corner) and select the Chart of Accounts page. Click +Add Account in the upper right corner and follow the prompts from there. See this article in our Knowledge Base for screenshots.
In REI Hub, you will still complete your bookkeeping on a property-by-property basis and track all your revenues and expenses for the specific property. At the end of the year, you can give that information to your tax preparer, and they can make any adjustments to the information as needed.