Ripustan märän liinan kuivumaan parvekkeelle.

Ripustan is the 1st person singular present tense form of the verb ripustaa = to hang (something up).

• Infinitive: ripustaa
• Present 1sg: (minä) ripustan = I hang / I’m hanging
  Finnish often omits the pronoun minä because the verb ending -n already shows it’s I.

Grammatically it’s present tense, but Finnish present tense commonly covers both:

• habitual present: I hang a wet cloth to dry on the balcony.
• near-future / planned action: I’m going to hang... / I’ll hang...
  Context decides which reading is intended.

Because liinan is the object in a “completed/whole object” form, and the adjective must agree with the noun’s case.

• Basic forms (dictionary): märkä liina = a wet cloth
• In the sentence: märän liinan (both words change)
  Here märkä → märän is the adjective taking the same case ending as the noun.

Liinan is in the genitive/accusative-looking form -n, used for a total object (often called the accusative in this context).
You use this when you mean you’re hanging the whole cloth (a complete, bounded object), not “some cloth.”

Compare:

• Ripustan märän liinan. = I hang up the wet cloth / a wet cloth (as a whole item).
• Ripustan märkää liinaa. (partitive) = I hang up some wet cloth / (focus on an ongoing, unbounded activity).

Kuivumaan is a verb form: the 3rd infinitive illative of kuivua = to dry.
This structure expresses purpose / result: to dry / in order to dry / so that it dries.

So:

• Ripustan ... kuivumaan = I hang ... to dry.

Yes, and the nuance changes slightly:

• kuivumaan = “to dry” (focus on the process, letting it dry)
• kuivaksi (translative) = “(to become) dry” (focus on the end state/result)

Both are natural; kuivumaan is very common for hanging laundry.

Because parvekkeelle is the allative case (-lle) meaning to/onto (movement toward a place/surface). You’re moving the cloth to the balcony to hang it.

Quick contrast:

• parvekkeelle = (to) onto the balcony (direction)
• parvekkeella = on the balcony (location)
• parvekkeessa = in the balcony (inside; usually not the normal way to conceptualize a balcony)

Finnish word order is flexible, but it affects emphasis. The neutral order here is: Verb + object + purpose + place
Ripustan märän liinan kuivumaan parvekkeelle.

Possible variations (different emphasis):

• Parvekkeelle ripustan märän liinan kuivumaan. (emphasizes where)
• Märän liinan ripustan parvekkeelle kuivumaan. (emphasizes what)

The core meaning stays, but the focus shifts.

Liina is a general word for a cloth, often something like a dishcloth / cleaning cloth / small towel-like cloth depending on context.
Other related words:

• pyyhe = towel
• rätti = rag (more informal)
• kangas = fabric/cloth as material

So märkä liina is very natural for something you might hang to dry.

A few common learner points:

• märkä → märän: the final -ä changes to -ä- + n and the vowel becomes long-ish in rhythm; say it clearly: märän.
• liina → liinan: straightforward -n ending.
• kuivua → kuivumaan: note the long vowel -uu- in kuivumaan.
• parveke → parvekkeelle: the kk is long (a “double consonant”), so hold it: par-vek-keel-le.

Finnish consonant length (single vs double) can change meaning, so it’s worth practicing.