Even though there is a lot in the Bible that is difficult to understand, most of it was written for clarity. That is not the case with Revelation. The last book of the New Testament is a classic example of the apocalyptic genre. The Greek name of the book, John's apokalypsis ("Apocalypse") makes it clear.
Revelation is just one of many apocalyptic texts that have survived from antiquity. The normative features of apocalyptic literature are well known, and Revelation has them in abundance. Apocalyptic books aim to reveal the future, specifically of the end of human history, in a cryptic fashion. Apocalyptic secrets are heavenly and not of earth. For that reason, the genre communicates its message in visions and uses angelic mediators to convey its secrets. John's book derives from visions he saw in heaven (see Rev. 4: 1-6; 9:17; 10:8; 12:10; 14:2; 19:11). Angels appear in Revelation over fifty times, and in many cases, they give John insight into those heavenly visions (Rev. 1:1; 17:7; 15; 19:9; 22:1,6). Despite this help, the content of the book is called a mystery several times (see Rev. 10:7, 17:5, 7).
Unsurprisingly, the book is riddled with symbolic language: unidentified "elders," spirits, living creatures full of eyes (Rev. 4-5); scrolls with seals, and celestial signs (sun, moon, stars; Rev. 6, 9); angels with trumpets (Rev. 9, 11); a great fiery Abyss from which emerge locusts (Rev. 9); a dragon (Rev. 12); beast emerging from the sea and the earth (Rev. 13); and the great prostitute (Rev. 17).
Basically, all of this imagery comes from the Old Testament (if the person teaching you Revelation never goes back to the Old Testament they are not teaching the book, but their opinion). Unfortunately for us, the imagery was symbolic to begin with, and Revelation at times changes the contexts and nature of the images. But our real disadvantage is that we come from another time and culture. While ancient readers would have instantly understood particular symbols, our understanding is anything but intuitive since we don't share their worldview. A deliberately cryptic book becomes even more obtuse. To have any hope of understanding the book, we need to first understand the meaning of the metaphors and symbols in the Old Testament and then read carefully for how John uses the Old Testament.
If that sounds like work, it is. And it gets worse. A lot hinges on discerning when the book was written, which in part depends on one passage in the book that is difficult to interpret. On top of that, it is unclear whether we should read the book as a chronological sequence of events or as a series of repeating cycles. The choice of reading strategy leads to dramatically different conclusions about the book's meaning. The dismaying truth is that Revelation isn't easy to understand because it wasn't meant to be easy to understand. For that reason, be very suspicious of anyone who tells you they have figured it out.