A year isn't going to cut it, you're looking at about a generation at least for any noticeable progress.
The problem is the lack of industrial base. Medieval society is a hair's breadth above subsistence farming. Technology is largely driven and supported by population pressures, without that they don't have the need to progress nor to maintain anything you ...
The situation you describe is almost exactly (part of) the plot from the book "A Fire Upon the Deep". Which in my opinion presents a very plausible level of success. In fact the specifications you offer (1 year-ish time period, lack of homeworld contact for the high tech people) match the conditions in the book very closely.
Basic sanitation, including the germ theory of many diseases.
Animal husbandy and plant improvement based on Mendelian genetics.
If they have the data and sensors, mid-term weather forecasts. Imagine a serf knew that there would likely be two more dry and sunny weeks before the harvest is due.
Food preservation technologies like canning (this requires jars ...
The other answers are excellent and thought provoking, but I’d argue that you need to invent the printing press almost immediately. Without reasonable speed of instruction, it will be difficult to teach the necessary skills to bootstrap many of the other improvements. Of course, this does require a significant push for literacy, but I'd argue that many of ...
If the goal is truly technological transfer, nothing meaningful is going to happen in a year.
There is a saying I've encountered while working in sales-related capacities, which is that you never sell a product, you sell the lifestyle that a product makes possible. I think that that's an important element here. Early interactions will be largely gifts, as ...
Not so much of an answer, but I'm not allowed to comment yet.
Anyway there is an Anime currently airing called Dr. Stone
featuring some guy who seems to know basically everything from todays science. The plot is, that every human was petrified for several thousand years and thus every piece of technology is gone. So he wakes up and finds some other humans ...
There are two sides to the problem. The first is technical and it's easy--if you can get the training tools and information to children, the next generation will have the full level of understanding and knowledge the race is capable of receiving, you are done training them and they will be as advanced as your children of the same age (assuming the same ...
Some basics which are freebees (as in, teachable immediately):
Some slightly longer-term (but simple):
The flying buttress in architecture
The caravel in ship design
The printing press
Utensils for food
CPR Emergency medical procedures
From a technology point of view, aliens can create and study a set of independent (advanced weapons required for negotiations with authorities) small closed guilds a-la "free masons" which would be able to keep (and develop very slowly) technologies on semi-religion basis in generations. The technologies should be a set of precalculated tables and some "...
Many answers so far identify the primary issue as social/cultural, but none feel like they hit that aspect squarely. I started thinking about it, then realised that the book "Connecticut Yankee in King Arthur's Court" was actually the prototype for a good answer. So I'll draw freely from that book, below.
Your problem is that your aliens are a small group ...
The 1632 series is a many-book-long exploration of this topic. In this series, a 1999-era West Virginia town transfers technology to early-modern-era Earth. The premise that that the Americans arrived via time travel implies that faster-than-light travel is possible, even if the Americans have no idea how.
The first technologies that the Americans seek to ...
since they are peaceful i guess computer (they can make advance robotic right?) that would help them for increase production and workforce to early industrialize them, or as revolutionary warfare like drone warfare.
that unless they dont get accused as satanic or witch by the mass or religions though.
and when i say computer, i mean an advance automaton(...