Puella quoque conatur, et tandem annulum sub mensa invenit.

Puella is nominative singular. In Latin, the nominative case is normally used for the subject of the verb.

So in this sentence, puella is the one doing the actions:

• conatur = tries
• invenit = finds / found

Because puella is singular, it matches the singular verb forms.

Latin does not have articles like English the and a/an.

So:

• puella can mean girl, a girl, or the girl
• annulum can mean a ring or the ring
• mensa can mean a table or the table

The exact meaning depends on the context or on the translation already given.

Quoque means also or too.

In Latin, quoque often comes after the word it emphasizes. So:

• puella quoque = the girl too / the girl also

That is different from normal English word order, where we often put also earlier:

• The girl also tries
• The girl tries too

Latin prefers quoque after the emphasized word.

Because conatur comes from a deponent verb: conor, conari, conatus sum.

Deponent verbs:

• have passive-looking forms
• but active meanings

So conatur looks like a passive form, but it means he/she/it tries or attempts.

This is very common in Latin, and learners often just have to memorize which verbs are deponent.

Conatur is:

• 3rd person singular
• present tense
• indicative mood
• from the deponent verb conor

So it means:

• she tries
• the girl tries

The ending -tur is the passive/deponent-looking ending for he/she/it in the present tense.

Latin often leaves the subject understood when it is already clear from the context.

Here, puella is the subject of both verbs:

• conatur
• invenit

So Latin does not need to say puella ... et puella ... unless it wants special emphasis. English also often avoids repeating the subject:

• The girl also tries, and finally finds the ring...

Tandem means finally, at last, or eventually.

It adds the idea that something happened after some effort or delay. So it suggests that the girl tried for a while, and only then succeeded.

That makes good sense with conatur:

• she tries
• and at last she finds the ring

Annulum is accusative singular, from annulus meaning ring.

The accusative is used for the direct object, the thing directly affected by the verb.

Here, the verb is invenit:

• she finds what?
• annulum

So annulum is in the accusative because it is the thing being found.

Because sub can take two different cases, depending on the meaning:

• sub + ablative = under in the sense of location (where?)
• sub + accusative = to under / beneath in the sense of movement toward a place (where to?)

Here the meaning is location:

• the ring is under the table

So Latin uses sub mensa = under the table.

If the meaning were movement, Latin could use the accusative instead.

If your book marks long vowels, this would be written sub mensā.

This is a very common question, because invenit can be ambiguous when written without macrons.

It can be:

• invenit = finds (present)
• invēnit = found (perfect)

In many printed Latin texts without vowel marks, both appear as invenit. So you must use:

• the translation
• the context
• or macrons, if provided

Since you said the meaning is already shown to the learner, that meaning tells you which tense is intended here.

Yes, the word order is perfectly normal for Latin.

Latin word order is much more flexible than English word order because Latin uses case endings to show grammatical relationships. That means Latin does not depend as heavily on position in the sentence.

This sentence has a natural Latin feel:

• Puella quoque conatur
• et tandem annulum sub mensa invenit

A few things to notice:

• the verb often comes late in the clause, especially at the end
• annulum comes before invenit, which is very common for an object
• sub mensa is placed before the verb as part of the buildup to the final action

So the order is not random; it is flexible, but still stylistic and meaningful.