There is great similarity between collecting pocket watches and submitting your annual tax return

In both cases you can either hire a professional or do it yourself.  The Tax Office doesn't care.  I suggest that you start building your collection by putting aside "play" money.  Let's say a couple thousand dollars.  Go online, do your research, buy the pieces you find attractive and learn from there.  Yes, most of the pieces will be terrible choices, bordering on junk, but this first phase of collecting is not about building collection, it's rather about learning about pocket watches.  In a year or so your success rate will grow.  The second option  is to acquire your pieces from dealers and fellow watch collectors who are knowledgeable and have years of experience.  Not only will the pieces be better but they also come with some kind of guarantee.  Have fun!