Learn Spanish (Latin America): Quedamos en reencontrarnos aquí el próximo fin de semana. - We agreed to meet again here next weekend.

The verb quedar usually means "to stay" or "to be left." However, when you use quedar en followed by an infinitive verb (like reencontrarnos), it becomes a verbal periphrasis (a grammatical set phrase) meaning "to agree to do something" or "to finalize a plan." Here, it means we agreed to meet again.

Is quedamos in the present tense or the past tense here?

It is in the past tense (preterite). For regular -ar verbs like quedar, the nosotros (we) form is exactly the same in both the present and the past tense (quedamos). Context tells us it means "We agreed" rather than "We agree."

Why is nos attached to the very end of reencontrar?

In Spanish, object pronouns must attach directly to the end of an infinitive verb. Here, reencontrar is the infinitive (to meet again), and the reciprocal pronoun nos shows that the action happens to "each other." Together, reencontrarnos means "to meet each other again."

Why does the adjective próximo come before the noun phrase fin de semana?