Please help with dental insurance, I am completely ignorant

I need help really bad, I have never had any type of health insurance let alone dental insurance, I am considering it now so I found Humana and I have so many questions but Googling isn't helping much

It says deductible: 50$ individual lifetime/50$ per person with a 150$ limit per policy lifetime (I have no idea what any of that means honestly)

Annual plan maximum: unlimited (Does that mean there is no limit theoretically to how much they would cover?)

Routine cleaning/exam/X-ray: you pay 0$ after lifetime deductible (Does that mean if I pay the deductible and of course my monthly payments that my exams/cleanings/x-rays will be free? Is there a limit to how many?)

Filings/simple extractions: you pay 50% after deductible (Same as last one, does that mean I will be paying half the price?)

A lifetime deductible will be applied to all services (What does this mean?)

The insurance costs like 22$ a month and as far as I can understand, which I may be way off, it seems almost too good to be true. I haven't been to a dentist in years because of the cost of it so if I could really get exams and cleanings for free after paying 22$ a month it sounds like a steal almost. Also no waiting period which seems nice. It's a preventative plan and luckily my teeth are not that bad so it's all I'm looking for really.

Can anyone help me understand? Or should I just call them and try to ask them? Do you think it'd be worth it? Anyone use Humana or this plan and do you have good or bad experiences?