Excel or similar spreadsheet software is all you need. Create monthly tabs and itemise your income for the month. Then itemise your monthly fixed costs e.g. mortgage payments, monthly subscriptions etc. Then list your variable monthly costs e.g. gas, electricity, phone etc. What you are left with is your disposable income. Categorise this figure e.g. day-to-day expenses, children's activities, general purchases, fuel etc. and set a realistic monthly budget for each. Set up a running total if you like (perhaps quarterly) so that there is no real issue if you are over one month and under the next as long as you are on track over the longer term.
Make sure you itemise and categorise EVERYTHING you spend or else you are wasting your time. Stick to what you have budgeted for in each category and you will start saving! Does anyone really need a take-out coffee every day? Or even every other day?