You should also see large whirlpools in between havens on the map as possible bastion locations. Clicking those locations gives you the ability to place your bastion there. I suggest seeking a general area that you'd like your bastion and then find a suitable location there. Rather than just clicking the LARGE bastion button on the map. Your bastion starts out on level 3. I suggest not building during pvp unless you have the ability to upgrade within less than a day to level 5. As well as having a massive amount of defense to hold it while you upgrade. Once at level 5 it cannot be downgraded to level 4. Level 5 is the milestone you have to reach before you can relax