honestly? as a fairly new player myself, my first recommendation in summary would be to check out the list of Activities and do those things! those will get you pebbles first and foremost, and sometimes get you a few other things:

the timer shows when these activities will refresh, but you'll get new ones added once you've claimed the rewards of one!
i would honestly say the best thing to do to get the ball rolling would be to follow the Campaign, and then Cook the food you get from that (if you check this thread there's a guide to what you can cook at what level, but also it's fun to experiment and just discover stuff!) - exploring in Campaign will often net you food, and will level up your lorwolves, so it's relatively self-sustaining as far as stamina-draining activities go
Mining is also a fairly cost-free activity, you don't need to equip a pickaxe or wheels to do it, you just send your wolf between the mining area and the furnace to mine ore and then smelt it!
as much as i'm recommending these, i also do recommend you start out Hunting as soon as possible - you need to have well-fed wolves for this, but there are hefty payouts for doing hunts, AND unique resources (i spent my first two days wondering where leather came from for some of the crafting recipes...)
speaking of Crafting - make ALL the bone paste you can. whenever you can make bone paste? make it. everything needs bone paste pretty much! i would also recommend once you have the materials that you make pickaxes and wheels often as these will make Mining a lot faster
once you have a few Pebbles, it's worth checking out the Mole Market, I would recommend you buy up all the food you can from there to give yourself a boost for other activities. that said, you CAN get a free item every so often from the Mole Market too
Fishing is also something i'd recommend checking out once you've got a few more pebbles, as earlier levels you'll want to pay Koda to fish for you so you're getting a more constant stream of XP, and early fishing can be quite slow
i hope this helps even a little and i hope you enjoy Lorwolf as much as i have been ❣️