The first-person speaker begins the poem by returning to the place where they "last met" someone important to them. Revisiting this place might be part of the speaker's grieving process, a way to come to terms with a newfound "absence" in their life.
Of course, readers don't actually know that the speaker has experienced a permanent loss yet; "last" can refer both to the final place the speaker saw this person and the most recent place the speaker saw them. The poem's title hints that the speaker won't see this person again, though the poem won't actually confirm this until line 4.
For now, the simple diction of this opening line establishes the poem's conversational, down-to-earth tone, and the end-stop adds a mournful pause before the speaker describes their visit. The speaker seems to be in a park of some sort, where they observe that "Nothing [has] changed." The place looks as it did "last" time; "the gardens" look just as pretty and well-maintained as they did during that previous visit, and the water fountains are still flowing as "usual."
These lines feature both parataxis and asyndeton, which add to the poem's straightforward, matter-of-fact tone:
Nothing was changed, the gardens were well-tended,
The fountains sprayed their usual steady jet;
Readers get the sense that these are just three examples among many that the speaker could choose from to illustrate the fact that this place looks like it always has. The lack of any "and" to connect these phrases also makes the lines sound quite casual, hinting at the world's indifference to the speaker's loss.
Assonance, consonance, and alliteration help to bring this garden imagery to life on the page:
[...] the gardens were well-tended
The fountains sprayed their usual steady jet;
There's the gentle alliteration of /w/ sounds in "were well," as well as the gentle chime of the short /e/ sound in "well-tended" and "steady jet." The hissing sibilance of "fountains sprayed their usual steady jet" conveys the splash of that water.
Altogether, the sounds of the poem feel lovely and deliberate, as though the poet has tended to the poem like a skilled gardener tends their grounds. These gentle sounds convey the beauty of this "place," which persists in spite of the speaker's pain.
Finally, these lines establish the poem's meter as a steady-sounding iambic pentameter: lines with five metrical feet that follow an unstressed-stressed pattern (da-DUM). Here's this meter at work in the first line:
I vis- | ited | the place | where we | last met
The poem features plenty of metrical variations. For example, the second line begins with a trochee (stressed-unstressed; "Nothing"), adding emphasis to the absence in the speaker's life. Even though the reader doesn't know much yet about the speaker's situation, this opening stress indicates that the speaker feels surprised—or, perhaps, offended—to find the gardens unchanged.