It will be easier to answer you if you give some examples.

@superboy97 said:

It will be easier to answer you if you give some examples.

Sure.

1. https://www.themoviedb.org/movie/20894-gostya-iz-budushchego — it is one movie. But it has 5 parts (episodes). Each of them is about 1 hour long. I have 5 video files, but can't use the DB for all of them
2. https://www.themoviedb.org/tv/43182-mary-poppins-goodbye — another Soviet movie, in 2 parts. But here it is just one record for the movie, while usually there are 2 video files.

According to Wikipedia Guest from the Future was originally released as TV miniseries and Marry Poppins, Goodbye as two part TV movie, so both belong to our TV section, where you can actually find them:

• Гостья из будущего
  
• Мэри Поппинс, до свидания (feel free to add missing episodes).

Movie entries are duplicates and as such are planned to be merged to TV entries.

Sources:

• Guest from the Future (English Wikipedia), Гостья из будущего (Russian Wikipedia)
  
• Mary Poppins, Goodbye (English Wikipedia), Мэри Поппинс, до свидания (Russian Wikipedia)
  

Note:
If the movies were originally released theatrically, they should be kept in our movie section as separate movie entries (single entry can be used only if the segments were screened with close release dates).

Thank you. So, the normal way is to add them as mini-series with episodes. Got it

@knari said:

Thank you. So, the normal way is to add them as mini-series with episodes. Got it

This answer apply to the 2 examples you have given.

The normal way is to search how they were originally released and add them according to this.

@talestalker said:

Note:
If the movies were originally released theatrically, they should be kept in our movie section as separate movie entries (single entry can be used only if the segments were screened with close release dates).

One question. There is another movie with 2 sections: https://www.themoviedb.org/movie/20874?language=ru-RU It was originally released theatrically as one movie, even having two sections. Now I see that it is presented ONLY in Movie section of the DB. Can I create another record in the TV Shows section as well, as a mini-series with two episodes?

If it was originally released theatrically as one movie, you can't create a record in the TV section for it. We only take in account the way it was originally released.