To download series on a laptop, you can use Netflix. You will need to have a valid Netflix subscription and download the Netflix app from the Microsoft Store. Once you have signed in to your Netflix account, find the TV show or movie you want to download and tap the title. Then, hit the Play icon and select the download option. It's important to note that some downloaded TV shows and movies with higher maturity ratings may not be available to watch offline.
If you're looking for free alternatives to download series, you can consider websites such as O2TvSeries, Light Downloads, Reqzone, GrabTheBeast, MKVHouse, YesMovies, CMoviesHD, WatchseriesHD, TellySeries, TopTvShows and TVseriesPage. However, it's important to exercise caution when downloading from these sites as they may not be 100% clean and safe. To ensure that the content you download is safe, it's recommended to use a reliable antivirus software.