Let's say your landlord agrees to give you $300,000 as an incentive for you to sign a 3-year commercial lease with regular monthly lease payments of $30,000. From an accounting perspective, you should treat the $300,000 as an annual reduction in your lease payments of $100,000. This means that when you receive the $300,000, it gets recorded on your books as a liability, amortized over the three years.
To do this in Offtoa:

• Record the $300,000 as a loan for $300,000 with a 3-year term (the term of your lease), 0% interest, and monthly payments of $8,333.
• Enter the annual Rent expense as $260,000 (not $360,000) - Billed to G&A. That's because your $300,000 cash payment from the landlord legally has reduced the annual rent by $100,000/year for the 3 years.
  

Note that the result of the above entries into Offtoa will cause Offtoa to make the following monthly entries in the (internal) general ledger of your company's pro forma:

• Reduction of the liability by $8,333.
• Reduction in cash by $30,000 ($21,667 for rent + $8,333 for reduction of the debt)

Meanwhile, if you purchase fixed assets (i.e., tenant improvements) with the $300,000 (the likely intent of the up-front payment by the landlord), you would record the purchase of these fixed assets just like you normally would, i.e., just enter them as fixed asset purchases in Offtoa. Note however that if any of the fixed asset purchases are items that you can take with you when the lease terminates for whatever reason, their lifespan should conform to IRS rules. If any are physically attached to the building, then their lifespan by definition is the term of the lease (i.e., 3 years).

Related Questions:

How to create a loan in Offtoa?

How to enter rent/lease payments in Offtoa?

How to enter a major purchase (fixed asset) in Offtoa?