You can normally carry one item per hand. This doesn’t preclude your having a shield strapped to your arm – but if you do, your shield hand can only hold (but not wield), a weapon or other handheld device, and you cannot use items that require two free hands, like a bow, rifle, or guitar.
You can also stow gear about your person, leaving your hands free. You can carry a one-handed item no larger than a sword or a pistol in a scabbard or holster on each hip; an item of that size or larger (e.g., a two-handed weapon like a rifle or a greatsword) slung over your back; and, with appropriate sheaths, one small item or weapon (like a knife or holdout pistol) per wrist or ankle. If you have clothing with pockets, you can stow one extra item per side pocket. A shoulder holster lets you strap a pistol-sized item over your chest. You can carry additional equipment in a bag, pack, or case, but it takes several seconds to remove it and get it ready.