Welcome to LW! Seconding Lunar Howler's advice to start with the starter achievements (under the Den dropdown), it helps with a lot of the basics. The mole market (site market) and flea market (player to player market), and the weekly event store are all under the shop dropdown. The professions are a good way to gather resources, and some can be found in the mole market as well. The mole market also gives you a random free item every so often (I forget exactly how long it is, it's every hour or 2 when the market cycles to new items), the button is to the left under Marvin.
For breeding, it works kinda like FR except it has to be done from the wolf page, not the nest. The breeding button is under the bloodline details on the right of the wolf's page, and will open a page with a list of all the options to breed with that wolf. You can preview potential pups from that page. You can also preview pairs on the Demo page (also under Den dropdown, similar to the scrying workshop on FR). Both options will also say if the wolves are too closely related to breed.
If you don't have wolves that you like together, the flea market also offers the options to stud wolves, allowing players to breed wolves without sending them to each other. Only male wolves can be offered as studs, so they're only useful if you have a female in need of a mate, but still pretty useful! Male progens can't be offered as studs, but female progens can still be bred using a stud.
For cosmetics, custom apparel is also an option (under Shop dropdown), that's the user made apparel.
For general advice, I'd recommend looking through the game guides forum, there's several useful guides depending on what you're interested in doing! One really helpful one is
Lady Rainicorn's Cooking Guide, which explains how to cook various recipes. Crafting recipes have to be bought, but cookings ones are discovered by adding different ingredients.
Also, you can do every pack's campaign! It doesn't actually switch what pack you're in, doing all 4 campaigns just opens up all the areas for you to go back to.
If you have any other specific questions, feel free to reach out! Also, if you run out of food, feel free to reach out - I run a free food thread and am happy to help! :)