The first step is to read the General Principles and the Ordinary to familiarize yourself with the structure of each hour.
The year is divided into seasons, identical to those for the Mass:
Advent
Christmas
Ordinary Time (between Baptism of the Lord and Ash Wednesday)
Lent
Eastertide
Ordinary Time (after Pentecost)
The psalter is divided into a 4-week cycle.
To know where you are, a website like
divineoffice.org/ will give you what week we are in the year and in the psalter (5th week of ordinary time, week I in the psalter), what saint (if any) is being memorialized (or what feast or solemnity it is). The site I mentioned even tells you where to find the right pages in Christian Prayer or the 4-volume Liturgy of the Hours, for each hour of the current day.
Eventually you’ll get the hang of it and won’t need the website any longer.
For memorials of saints, you start with the proper of the saint him/herself. Anything not in the Propers will be in the Commons for the type of saint, e.g. commons of the Blessed Virgin, of martyrs, of doctors, etc.
For memorials, unless otherwise specified the antiphons and psalms are the of the day in the 4-week cycle. For feasts, at Morning and Evening prayer, psalm and antiphons are from the Propers or Commons as specified but for mid-day prayer, from the 4-week cycle. For solemnities, same thing, except for the use of the Gradual Psalms at the mid-day hour.
It would almost be worthwhile to have on this form a sticky at the top posted by someone knowledgeable giving the indications as to what day today is, using the General Roman calendar.