Welcome back! Start with quests. A lot of quests give exp rewards which will get you decent base stats. Also quests will provide you further content accessibility to OSRS gold thing, monsters and slayer masters. After quests, continue using slayer. Personally when I came back I just started out doing quests in the sequence which they were published by looking on the old school wiki. I strongly suggest watching Slayermusiq1's guides on YouTube, if you do not care about the story line, he will help get them through quickly by telling you which dialog options to choose.

No problem! Would recommend you start with Waterfall quest, it is super easy and will provide you a few strength and attack exp. There's a few fairly easy. Town, dwarf cannon, priest at peril, nature spirit, fairytale shrub gnome village, expansive tree and part 1. Also complete all of the f2p quests since they're very easy and quick, they will offer you some fast exp and pursuit points. Following those quests I would suggest aiming for monkey madness (for your dragon scimitar) and get as far as possible through the recipe for disaster quest, ultimately for barrows gloves.

Really though, you can not go wrong regardless of what quest you do, you'll have to do them as they're a requirement for something. Do the quests that give farming experience to you and start doing herb conducts to make some money. Doing Recipe for Disaster pursuit for accessibility is an essential for every normal accounts, and working towards it will allow you to train all of your skills.

I keep on with slayer, divided by as many quests as you can stand to do lol. Otherwise, I would recommend going for 50 in most skills and cheap RS gold knocking from the simple and/or medium achievement diaries. Trust me it's better to get those completed early to start reaping the rewards as soon as possible. Also huge notice, do not buy bonds with gp. It'll keep you bankrupt for a long time that is good. You start accumulating you won't have to use welfare gear when you start bossing. That is most new players largest error, and that means you find some lvl 100s using 50m+ bank and some that can not manage a bond.