In order to access .onion sites, you will have to take the help of Tor. Tor can be accessed through Tor browser only. TOR browser is like Mozilla only but there are enhanced features for more privacy. Since, some of the onion sites are illegal as well; you want to cover up yourself while accessing these sites. If you are a newbie, it is recommended to run Tor browser with default settings only. If you play with the settings a lot, you can mess it up and thus the user privacy might get exposed due to changed settings.
In order to find a site on The Dark Web, you just have to search on Google. But on the dark web, you cannot find an onion site in a similar fashion. You will have to take the help of sites like The Hidden Wiki of The Dark Web which contain the list of indexed onion sites. Here are some sites that you can use to find active .onion sites:
On The Hidden Wiki, you will find links related to cryptocurrency services, darknet marketplaces, social media related services, website hosting and domain related services, and much more. Make sure that you are using the updated version of the site as old versions have many broken links and you will just waste your time with them.
This site also contains a large list of .onion sites but there is an advantage that it also provides a description of these sites. The best part is this website is available on the dark web as well as on the clearnet as well. You can get the most updated dark web links of 2020 by going to this website.
Torch is a search engine made for the TOR browser. However, it is very much different from regular browsers like Google. Like for instance, if you search for Facebook on Google, you will find a social networking website. But if you search for Facebook on Torch, you will get links to Russian hacking forums. With some practice, you will learn how to use the search engine Torch.
In case, you are not able to get desired search results with Torch search engine, you can try Not Evil. For instance, if you will search for Facebook on Not Evil, you will get the result for onion Facebook site.
There are a number of myths associated with the dark web. You thus need to be very much careful while browsing sites on Tor browser.