Our practice this year has been to read the Psalms, which contain 5 books, book by book. Now we return to Book V (Psalms 107-150) . The first series of psalms 111-118 are the “Hallelujah Psalms”. The “Egyptian Hallel (ps 113-118) was sung for the three great pilgrimage festivals, Passover, Weeks, and Tabernacles. The “Psalms of Ascent” (ps 120-134)  were used by pilgrims to or from Jerusalem. Psalm 136 is the “Great Hallel” for Sabbath services. Psalm 146-150 end the book with “Praise the Lord”.  Psalms 107 and 119 may be introductory psalms. 107 introduces the fifth book and 119 introduces the psalms of ascent.  Psalm 137 is untitled and unclassified. There are psalms of David in this book, 108-110 and 138-145.

You will find an introduction to the Psalms, here.

Here is a prayer from Gregory of Nazianus (329-389) who was an early Church father.

Lord, as I read the psalms let me hear you singing. As I read your words, let me hear you speaking. As I reflect on each page, let me see your image. And as I seek to put your precepts into practice, let my heart be filled with joy. Amen.
Psalms 120-134 are each titled “A Song of Ascent”. Most likely these psalms were sung by people on their way to and from Jerusalem. Alternately, it may refer to the steplike parallelism in many of these psalms
Psalm 120: A lament This psalm is an individual lament. Verses 2-3 are a complaint(slanderous attacks), verses 3-4 are a petition for the punishment of enemies, verses 5-7 are another complaint( exile far from Jerusalem.
Psalm 121: Confidence in God’s care.  Verse 1 is a question, verses 2-8 are the reply. Notice the steplike parallelism with repeated words,  “not/ neither slumber”, Keeps/keeper.  The “hills” may refer to the “high places” where other gods were worshiped. Jerusalem also is on a hill. Verse 1 can be read either as being worried about danger, false gods in the hills or as trust in God in Jerusalem. Notice in verse 6 there is a reference to the sun not striking the psalmist, but also 6b refers to the moon not striking the psalmist. Recall that in the ancient world, the sun and moon were deities. God is the protector from other gods.
Psalm 122: A song praising Zion. Verses 1-5 celebrate the city of Jerusalem and the pilgrims arrival. Verses 6-9 are prayers for peace. “The house of the Lord” is the Temple.
Psalm 123:  A group lament. Notice that God is compared to a mistress. Female imagery about God is unusual in the Psalms.
Psalm 124: A community thanksgiving. Notice the metaphors for the dangers the community has been delivered from.  Again notice the step parallelism “if it” and “then”.
Psalm 125: A group lament: Verses 1-3 are an expression of confidence. Verses 4-5 are a prayer for help.
Psalm 126: A community prayer for the return of exiles. Verses 1-3 are an opening statement and then verses 4-5 are a prayer. Notice the step parallelism

Here are several good sources to aid your reading of the Psalms

Anderson, Bernhard W., Katheryn Pfister Darr, Understanding the Old Testament Abridged fourth Edition. (Upper Saddle River,New Jersey: Prentice Hall) 1998.

Clifford, Richard, “Psalms” in The New Oxford Annotated Bible with Apocrypha: New Revised Standard Version.Coogan, Michael D.; Brettler, Marc Z.; Perkins, Pheme; Newsom, Carol A. (2010-01-20) Oxford University Press. Kindle Edition.

Stuhlmueller, Carroll, “Psalms” in  HarperCollins Bible Commentary Mays, James L. ed.(San Francisco: HarperSanFrancisco) 2000.

McCann,Jr, J. Clifton “Psalms”,in The New Interpreter’s Bible Vol 3, Keck, Leander E. ed. (Nashville: Abingdon Press) 1996.