Short dramas are made as a series of short episodes, not as a single film, yet you can watch one from start to finish as if it were. On DramaSpot each episode rolls into the next, so a typical 55-episode series plays through without you lifting a finger.
Why people look for the full movie
A whole series is roughly feature length, so many viewers prefer it in one sitting. Videos labelled "full movie" on sharing sites are usually stitched together by someone other than the studio and are often incomplete or removed.
Watching in one sitting
Start episode 1 and leave automatic next episode on. Use full screen if you like. If you stop midway, the show page offers to resume at the same episode and moment the next time you open it on that device.
Short series to begin with
How these were chosen: by episode count alone, shortest first. We have no ratings, so this says nothing about which is good.