I feel like as a newcomer it's important to find a niche where you know your stuff, because otherwise it's gonna be overwhelming. Lab could be that niche if you think it's something you can do a bunch of times and have fun with it
Don't bother killing mobs in lab, do not pick up rare items except maybe rings and amulets if you are doing chaos recipe. Obviously pick up currency, 6-Socketed items and the occasional map
You should look up each day's labyrinth at poelab.com. People usually only do stuff that's on the main path to izaro to keep the run as short as possible. The main objectives are argus (always drops a treasure key) darkshrines for a possible extra key plus a chance to get an additional enchant, and gauntlets/puzzles. Note that these can have 2 different chests at the end; curious lockbox and labyrinth trove, with the lockbox giving treasure keys.Sometimes it's possible to scout ahead and see if it's worth doing the gauntlet.
You can also get up to two additional keys from izaro by making the fight harder on you. I recommend you check poelab for that.
As for the chests at the end, quality gems are a good thing to look into. Check the gem section at poe.ninja to see which ones are worth some chaos.Vendor the worthless ones to get GCP's to up the quality of the good ones to 20%. You will also get high tier maps sometimes. Otherwise there'll be lot of raw currency and atziri fragments. If you get a lot of keys on your runs all the time it's almost impossible to not make money without even hitting the enchant button
Speaking of enchants - I'd highly recommend you start with enchanting boots for two reasons
First, if you start farming lab you will be slow. That's totally fine and there's no use trying to speedrun when you're just getting to know it. Combine that with how there's a few hundred helmet enchants and only around 20 or so boot enchants chances are you will never hit a good enchant on a helmet, while boots will net you a steady income. But you do lose out on the potential of a super lucky 30ex+hit on a helmet, which I think is okay
Atziri's step are good boots to begin with. Only buy some with perfect dodge roll and high life roll. Should be very cheap. Good enchants to get are : damage leeched as life and mana, life regen, added lightning damage, attack and cast speed and elemental penetration. Probably missed something, always price each enchant until you know what's worth some cash.
I probably made mistakes somewhere, but i hope it helps you get things started. Best of luck and merry christmas!