Learn Spanish (Spain): Solemos ver esa serie por la noche. - We usually watch that series at night.

The verb soler means "to usually do" or "to be in the habit of doing" something. It is always followed by an infinitive (an unconjugated verb). Here, solemos (we usually do) + ver (to watch) creates the meaning "we usually watch". You don't need a separate adverb like normalmente when you use this verb structure.

Why is the word for "series" singular in Spanish here?

In English, "series" is spelled the same whether it's singular or plural. In Spanish, serie is the singular form (meaning one specific TV show), and series is the plural. Since they are watching one specific show, we use the singular esa serie. Also note that it is a feminine noun, which is why it uses esa instead of ese.

Why do we use por in por la noche instead of translating "at" directly?

In Spanish, we use the preposition por to refer to general parts of the day, such as por la mañana (in the morning), por la tarde (in the afternoon), and por la noche (at night). You only use de instead of por if you are stating a specific time on the clock, such as a las diez de la noche (at ten at night).