Steering awkward and squeaky wheels.

Question

Recently I purchased a brand new Bertini Bidwell 905 secondhand. I was mortified when we went out for our first walk. The steering was extremely awkward, like a shopping trolly with a mind of it's own. High pitched squeaking noises came from the wheels.Having the wheels fixed or independnant made no difference either.We are reluctant to start removing covers behind the wheels in case we can't get them back on. We do not have an owner's manual or video. Please would you advise us what to do.Kind Regards,Citrus3