You and the company are two completely separate legal entities.
The company must sell them to you.
If there was a gain on disposal, the company must pay the equivalent of CGT.
You must buy them i.e. transfer money into the company in exchange for the shares.
You must pay stamp duty on them.
This should all be done at market prices.
If you do it at less than market prices, you will be subject to all sorts of tax and other compliance calculations.
The actual process itself is fairly straightforward. Your stockbroker will do the paperwork for you and charge less than the normal commission - but ask beforehand.
Brendan