The Basic tab lets you configure the expense item. Most expenses will be a budget - this is for anything where you budget a certain dollar amount for the expense. You can also create a quantity based expense, such as Computers where each unit costs an amount, or a computing budget where each server instance costs a certain amount. Quantity based expenses are useful for expenses that are linked to other items, such as one server instance spun up for each enterprise subscription sale.
The Links tab lets you generate leads/sales from expenses to model lead generation driven revenu growth.
[Pro] CAC/COGS lets you allocate expenses towards CAC and/or COGS.
[Pro] Terms/Accrual lets you specify payment terms and expense accrual policies.