Well, it's a bit confusing, and like everything else there are pros and cons...but here are the most common options:
1) If you, your intended or the families are religious, then you will likely go down the church route. Contact your local priest or pastor and they will guide you through the process. Usually you can have some input into the ceremony, readings/music etc. , but remember it is a sacrament, so unlikely you can have anything too way out.
2) You can have a civil ceremony (what we used to call " getting married in a registry office"). This is a non-religious, legal ceremony, performed by a civil servant. They can marry people Monday- Friday only, either in the office or in an appointed venue, but not outdoors. These ceremonies are usually quite short and simple, no fuss.
3) In 2013, Ireland passed a law such that Humanist weddings would have legal status. These ceremonies can be delivered any day of the week and in any suitable venue. The ceremonies are delivered by members of the Humanist Assoc. of Ireland. You can have input into the ceremony, but there can be no mention of God or any religious aspect to the service.
4) Celebrant- led ceremonies: These can be performed indoors or outdoors, any day of the week. Any one can perform a wedding ceremony for you - your pal, uncle, sister.. but most celebrants will have completed a Celebrants course, such as that run by IIOC in Ireland. This course teaches people how to craft and deliver a very personal ceremony. The drawback is that these ceremonies have s no legal status. You will still have to " get married in the registry office" ( unless the celebrant is also a solemniser). Maybe this is fine with you, but some couples, understandably want one ceremony and one wedding date.
For a the ceremony to be legal it has to be delivered by a legal solemniser; these are people listed on the register as having legal status to marry you.
Yes of course I am an accredited celebrant and legal solemniser - that's what I'd choose if I was getting married!