The liquid (net) salary is what you actually receive. Gross wages are what you receive before any withholding or taxes are taken out. For example, if you earn $1000 per month, that would be your gross pay. That amount is reduced by (*) taxes, health, and welfare allowances, among others, which let's suppose the sum of USD$150. Your liquid or net salary would be USD$850.
When you apply for a job on Get on Board, you must specify your expected net salary in dollars. Remember to use whole numbers and in increments of 50 (eg. 900, 950, 1250).
(*)These discounts vary according to the country you are in and your own contracted pension plans.