Its normally not good to post by journal to vat liability as there are transactions available in the product to handle nearly everything you need and it does it well and no mistakes.
However in saying this there is in desktop and option available.
If its for normal sales then it quite simple.
You have to choose the vat control account and the vat agency should appear in name column.
Select the vat item you wish to use to post to the correct vat boxes. This is under Vat item column.
Run vat unassigned vat report afterwards to show if you have posted correctly.
If you tell us what you are trying to post we probably can show you how to use desktop to get the result you want .
