As the rental income is un-earned income, you will have to report it under self-assessment on a Form 11 or Form 12
The good news is that the tax on the rental income for 2022 will not be due until November 2023. You will have to file a tax return in 2023 detailing the income, the allowable costs and the profit. When you file the return, Revenue will calculate the tax due and it need to be paid by end October/mid November 2023.
Normally under self assessment you have to pay preliminary tax in the year of assessment, but as this is your first year this does not apply. In Oct/Nov 2023 you will have to pay the tax due for 2022 and preliminary tax for 2023 based on either the tax paid for 2021 or your estimate of the tax due for 2023 - so in effect you will have to pay two years tax in one go. After that, you will have to pay any balance due plus the preliminary tax for the next year.
If you have records of the expenses, you can probably dispense with an accountant but using an accountant at least for the first year, will probably help to make sure you claim the correct allowable expenses