Yeah, it can be pretty intimidating. I started playing in 2014 so I can't really even remember what it's like to not know PoE, but I remember it was a long road. Some unsolicited new player advice:

Don't sweat it too much. Respecing is a little tough but as long as you focus on picking up notables (the larger passives with a small gold rim) you won't need too many points to patch mistakes unless you went way off course. Just grab life nodes and all the damage notables around them that apply to your skill and you'll make it through the campaign easily. Keep your resistances at 75% after act 3. Pick 1 skill gem to buff, and try to get 4 linked sockets to support it. Don't forget to do all labyrinth trials and ascend at acts 3, 8, 10, and maps.

Ways to screw up a build in the skill tree: Grabbing irrelevant passives. Don't grab attack stuff if you're a caster and vice versa, don't grab crit stats for damage over time, don't get spell damage for spells that deal damage over time if they don't specifically state the spell damage will apply to their effect (this only really matters for Righteous Fire, but it's worth mentioning because it's a common mistake in a beginner friendly build). Grabbing way too few life nodes (get at least 300 life by the time you finish each act, so 300 life at the end of act 1, 600 for act 2, etc). Grabbing stats that are not very useful in most situations (% armor, % evasion, % energy shield, stun).

Other than that, a build guide isn't absolutely necessary IMO. It's a complicated game but people make it seem like even the campaign is super rough, if you've played an ARPG before the complexity only starts to get ridiculous when you hit like level 85. Before you get to that point, the game is not really mechanically complex.