The Liturgy of the Hours is the official prayer of the Church. It is designed to sanctify the day. When I was ordained a deacon, I made a promise to pray the Liturgy of the Hours every day for the rest of my life. Every bishop and priest prays them daily. Many deacons, religious communities, and even many lay people also pray the Office.
It has many different names that all refer to the same thing: Liturgy of the Hours, Office, Breviary, LoH.
It’s not really like the Rosary at all, I’m afraid. The only similarity is that there are 150 Psalms, and prior to the additional Luminous Mysteries, there were 150 Hail Marys prayed in a full 15 decade Rosary. The idea behind the Rosary was so that “common folk” who were illiterate could pray the 150 Psalms with the literate priests and monks. This isn’t a problem anymore.
The LoH is divided up into five “hours,” or offices: the Office of Readings, Mornign Prayer, Daytime Prayer (which is further divided into three sub-hours: Mid-Morning, Mid-Day, and Mid-Afternoon), Evening Prayer, and Night Prayer. Of these, Morning and Evening Prayer are the most important. There is a four week cycle of Psalms that are prayed, such that, if one were to pray each office for four weeks, he would pray almost all of the 150 Psalms. It’s not quite all of them though, as some are omitted.
Certainly anyone can pray the LoH, either alone or in a group. However, a word of caution…it can be quite confusing the first few times you do it, because things change depending on what the date is, which liturgical season you are in, and other things. Once you do it a few times, it’s a piece of cake, but the first few times can be confusing. If you’re just starting out, I would recommend starting with Night Prayer, as it is the shortest hour and the easiest to learn. It only takes about five minutes to pray. Even the long hours only take about 15 when sung.
As for where to start, you can pick up a one volume version of the LoH called Christian
Prayer, but it will not have everything in it. If you want to do everything, you will need the four volume Liturgy of the Hours. There are also a number of apps available. The one I recommend and often use is iBreviary. I think it’s free, but it might be a dollar or two.
Happy praying!