find the volume for Lent and Easter. Read the introductory material thoroughly. A lot won’t make sense, but a lot of it will, you need the back ground.
to pray the LOTH right away, find the 4 week psalter. since we are on Monday of the 6th week of Lent, we are in the 2nd week of the psalter. Pray the psalms for each day, morning and evening prayer, with the antiphons for Lent (until Easter, then it will guide you which antiphons to use. If the antiphons are too confusing right now, skip them. Remember, Alleluia is not used in lent)
then you will see it refers you to the proper of the season for the readings and the rest of the hour (the front third of the volume). find the section for the 6th week of Lent, Monday, evening prayer, and continue. Where it gives the antiphon for the Canticle of Mary (My soul magnifies the Lord), you either have it printed on an insert, or it is in the center of the book, where it gives the “backbone” of each of the hours.
tomorrow, for morning prayer, spend some time with this center part of the book, that describes how the hours “work” and what is contained for each hour.
If the seasonal readings etc. are too confusing, you can stick with the 4 week psalter until you get the rhythm. Easter Sunday go back to week one in the psalter. The hitch for Sundays is that there is no evening prayer for Saturday, because Sunday properly begins then, so you have Evening Prayer 1 (prayed about dusk on Saturday evening), then Sunday Morning Prayer, then Sunday Evening Prayer 2 (prayed about dusk Sunday evening).
the office of readings can be prayed anytime of day or night. they also have psalms in the psalter, which can be optional for now.
try to find some Benedictine Oblates or others who pray the Office regularly to show you how. It really is not as confusing as it looks if you start slow. There are lots of other threads on this topic with good links for doing it on line which will guide you.
the little booklet you found you should hang on to, because it will still tell you where to find your “place” in the psalter everytime the season changes (Monday after Pentecost, Ash Wed etc.) as a general rule, when the liturgical season changes, go back to Sunday Week One, i.e.1st Sun of Advent, 1st Sun after Christmas, 1st Sun of Lent etc. You will switch to the volume for ordinary time after Pentecost, and things will be much easier to follow.
Don’t worry about saint days and feasts just yet until you get comfortable.
If this is blowing you away, if you pray the psalms from the psalter, and read the readings in the Office of Readings, you will have very good meat for prayer and meditation.