Go to the communities page for your instance, set it to all, and scroll through the first several pages adding anything that sounds interesting. Don't worry if there are duplicates, sub them all. The search for any favorite topics and add those communities, too. Then browse by subscribed»new going forward.
Also check https://lemmyverse.net to see list of all known communities. If you click the home icon, you can set your instance (which is lemmy.world for you) and all the communities will open on your instance correctly. All the instance things might be confusing at first, but you'll grasp it soon enough, no need to worry about that.
I would think that holding your poop for any amount of time would be no good. I usually deposit mine directly into a convenient flushable porcelain receptacle, no extra handling required
Search for communities that interest you! It's just like Reddit, once you curate your own experience you'll enjoy it :) check out my list of casual/fun communities on Lemmy, or browse Lemmyverse for a list of all of them.
If you are using your phone, get one of the mobile apps (Voyager, Liftoff, Infinite, Connect or Sync for Lemmy) and then use it just as with reddit. You already have created your account, thus chosen your instance, which is the biggest 'This is different' topic.
Search https://lemmyverse.net/communities for any communities you may be interested in. Many of them have the same or similar names to reddit subs. Also, subscribe to !newcommunities@lemmy.world. Once you have a few, flip your feed over to “subscribed” and browse your custom feed. Occasionally pop back into All to see if there are any other good ones you may have missed.
If you hate the web version of lemmy like I do, check out the mobile apps, which tend to have a more reddit-like design.
And once you’ve done all that, the only thing left to do it shitpost.
On your homepage, you have some options at the top for what to display.
The first option is Subscribed/Local/All. The default is Local - change it to either Subscribed (If you like subscribing to communities) or All (If you prefer to just see everything). Keeping it on "Local" is a pretty poor way to use Lemmy - it'll only show you posts from lemmy.world and never from any of the other Lemmy instances. This goes for when you're searching for communities too - make sure you set the search to "All" and not "Local".
The second option is how to sort - with the default being "Active". "Active" is a bit too slow to update for most people's taste - you might find you like "Hot" a lot more. You can set the default for both of these options to whatever you want on your settings page.
When browsing, if you find a certain community (subreddit) consistently puts posts in your feed that you don't like, there's a handy button to block that community if you go to it, in the top right.
Past that, just do your best to be active - more active than you may have been on reddit, because Lemmy is a lot smaller. Upvote posts you like, comment on posts where you have something to add, and post things you find elsewhere.
I go the other way and hide the communities I don't want to see (e.g., I'm not into yiff). I do subscribe to ones I want to see, too, but mostly I view all with some filtered out. New communities are being developed every day and I might miss some with the subscribe method.
O damn, I didn't even know this! That's awesome, is there a list to check out? I probably will stick with old.lemmy.world, but that's cool that there are other layouts/looks.
First I tried a few mobile apps, sticking with Sync for Lemmy for now.
I also went to Sub.rehab, filtered by highest active users and subscribed to the communities I was interested in. Then subscribed to a few I was interested in even if it has a low amount of users.
pick your instance in settings (the gear) then all links will open in your instance and you’ll be able to subscribe in one click. the site is sortable and filterable - highly recommended