Sounds easy
Usually not so easy
Be extra careful when taking the bolts out. Use penetrating spray well before even trying to take them out, otherwise you might brake one of (the stock ones are very weak). Good luck finding the problem, but it ticking is a symptom of a broken exhaust manifold or missing bolts. Usually though it is more apparent when the engine is cold, since when it heats up, the metal expands and usually seals small gaps.