Welcome to the site that you should probably make your home page now that you dove in!
What are you looking for in a Nem? Carpet, plain, exotic color?
Time is your best investment for our reefs. Take you time and it will be there for years, I would heed the already given advice, and wait a while before adding one.
I agree that the clowns in a nem is amazing to watch/behold, but, a sick and dead nem is horrid, ask how I found out. Unfortunately I was a young reefer 20 years ago when I tried a “common” one.
Now I would wait at least 6 months before introducing one in a well stocked (bacteria and fish) and fed tank.
But, my friend introduced one after 2 months and it is extremely healthy after almost a year, but as always in reefs, ymmv.