"PAYE tax" and credits

Hey there r/AskIreland. Hope you're all well and enjoying the last weeks of sun we'll have.

After 2 months unemployed, I've been hired by a company which pays me weekly. So far, so good. But when I got paid, I was credited left than half of what I was expecting. Upon checking my payslip, I noticed a certain "PAYE (pay as you earn) tax".

Is there anything I can do to get this money back? My boos told me to check ros.ie and/or Revenue, bust most of it doesn't make sense to me (English isnt my forst language, but I can thrive).

Thank you allin advance!