When using our Balance Sheet feature, you'll make entries in your budget for your revenues and expenses, but to be able to create a balance sheet and a cash flow forecast these entries need to flow into your A/R and A/P accounts, and onward to the bank account.
To facilitate this, we need to define all your A/P and A/R accounts as Cash Flow Through accounts. This is just a simple check box in the settings page for each account. Go to Settings > Categories, find the appropriate category/account, click the pencil icon on the right, and you'll see something like this:
The Cash Flow Through box must be checked, and the Target Categories field will be prepopulated with the default bank account. Now any entries made in the revenue and expense accounts will flow through the appropriate A/P or A/R accounts based on any terms that you've defined before hitting the bank account.