I've incorporated a few days ago, what is the best way of dealing with taxes (like if you're a freelancer do you manage them yourself), how do you take money out of the business bank account etc?
If you're not comfortable doing the accounting yourself, hire an accountant to do it for you, especially if you need to worry about VAT.
There is software you can use to help you with the accounting but at least when it comes to doing the actual submissions and tax payments, hiring an accountant is recommended. It's what most people do.
I would 100% use a tax preparer as HMRC will come after you eventually. I gave a breakdown in the Mentor Group on how to do it all in the most tax efficient way if you are resident in the UK. Otherwise if your not resident in UK then its even much simpler.
Someone who specialises in this area will confirm but I think running a UK ltd as a Serbian, while living in Serbia with no ties to the UK would make it a non resident company so the taxes are handled by Serbia.