Yes I am a cadet in audit. It's really quite difficult to say what exactly we do but it might help if I tell you the point of an audit (which is also referred to as our "Assurance" line of service). The point of assurance is (as the name means) to give confidence; and this can be done in many ways and for many reasons. For example, managers in a company might want to know where they are losing money and identify what needs to be done and to make those decisions, they need someone to give them information. Alternatively, shareholders/investors may want to know which company is making money (profitable) and will read this information in the company's published financial statements which describe the performance of the company throughout the year. Whilst it can be prepared internally such as financial statements or just a special report, there's a lot of potential for there to be bias, errors or simply, the people writing it don't really know either. That's where we come in. We spend a lot of time learning and understanding the business, and then we either vouch for their financial statements such as in a statuatory audit as required by law or we write a letter/report for them. Either way, as part of assurance, this can mean we do a lot of special procedures which will be specific to each firm. However at the very very basic level, this includes test of detail whereby you randomly select items in their systems and ensure that the details were correctly entered (ie. match invoice and "tick and bash") and also control validation (ie. ensure that there are controls in place to prevent people doing dodgy things or making mistakes). At a more advanced level such as after 6 months or so (at least in my experience) you will be able to decide for yourself what to do when there's an exception (ie. something doesn't work out or isn't correct) and can determine whether or not it poses a risk to our audit opinion (that is, whether or not we believe the document we are auditing/vouching for is a true and fair document- that is, it may have a few small mistakes, but nothing which will be substantial enough to affect any decisions made). Furthermore as you become more skilled you will also be asked to plan the audit such as the level of work/testing required, materiality (how to tell when something is too small to care about), analytics (using common sense approach rather than ticking and bashing- eg. if sales goes up, you'd expect amount of goods sold on credit to go up, which results in probably a higher number of bad debts- debts not being repaid, which is likely to increase bad debts expense, etc..), and then you will even be able to assist in drafting management letters (ie. suggestions to the business on how to improve such as... stop trying so hard to get new customers if alot of them are bad debts because you give credit out too easily; or improve controls over the computer systems to make sure people dont' commit fraud, etc..).
Sorry if this is too vague for you but I think I've given a pretty good explanation of what we do, and more importantly, why we do it. The reason why the 'why' is so important is simply that in the long run, whilst we do have set guidelines and procedures, as you become more skilled you have to understand the importance of knowing why you're doing something so you can identify and focus on the key risk areas, rather than simply doing what you did last year or were told by someone else to do. Companies and business are always changing, and as a result, you need to always find new ways to 'test' or 'identify key risks' in your clients' businesses.
Btw this is from a Financial Assurance perspective. That is, we are external auditors and typically work on financial-related data such as financial statements. Business Assurance and internal audit is something similar but quite different in other ways- they focus more on controls to minimise fraud and issues; and as external auditors, we rely on this control work to give ourselves comfort too!