Learn Finnish: Nämä agentit ovat täällä ostaakseen uudet valepuvut. - These agents are here to buy new disguises.

This is the structure you are currently learning: the verb's dictionary form (ostaa) + the translative marker (-kse-) + a possessive suffix (-en). Together, this forms the "in order to" structure. The possessive suffix shows who is doing the action. Since the agents are "they", we use the third-person suffix -en.

Why are uudet valepuvut in the T-plural form instead of the partitive?

Because the agents intend to buy the whole disguises, not just "some" disguises. When an action is seen as complete, Finnish uses a total object. For plural words, the total object is formed using the nominative plural, which means adding a -t to the basic form.

What is the literal meaning of the compound word valepuvut?

It is made up of vale-, which means fake or false, and puvut, which is the plural of puku (suit or costume). Together, "fake suits" translates to disguises.

Why is "here" translated as täällä instead of tänne?

Finnish uses different words for "here" depending on movement. täällä is used for a stationary location, which fits here because the agents are already at the location (ovat täällä). If the sentence said they were arriving or traveling to this place, you would use tänne.