Brugge for whole day

The best part of Brugge for me (and I loved it!) was wandering the streets after all the tourist had left. It is one of the most beautiful cities at dusk I have ever seen. My garden salad at Cambrius (www.cambrinus.eu) was one of the best I have had while traveling. If interested be sure and make reservations. We found it and other great pubs in the RS Book.

Honestly, I'd skip both the Choco-Story and Friet Museum lest you'll miss the best of Brugge! Buy your frites on the street and munch as you go.

Must do/see (strictly from my perspective):

Markt (the belfry is here) and Berg, for the architecture:
https://www.visitbruges.be/en/belfort-belfry
https://www.visitbruges.be/highlights/burg
https://www.visitbruges.be/highlights/marketsquare

Church of Our Lady:
https://www.visitbruges.be/en/onze-lieve-vrouwekerk-church-of-our-lady

Sint-Janshospitaal (St John's Hospital): 800 years of history and a really good art collection
https://www.visitbruges.be/en/sint-janshospitaal-saint-johns-hospital

Ten Wijngaerde Beguinage:
https://www.visitbruges.be/highlights/beguinage

Jeruzalemkapel (fascinating):
https://www.visitbruges.be/en/jeruzalemkapel-brugge-jerusalem-chapel

Groeningemuseum (great Flemish Primitives):
https://www.visitbruges.be/en/groeningemuseum-groeninge-museum
You could skip this if art if not your favorite thing and make do with what's at Sint-Janshospitaal.

A walk through Hansa Quarter for history and architecture:
https://www.visitbruges.be/hansaquarter

There's more but I'd spend the rest of your time just checking out the lovely little streets and some of the canals. A walk along some of the city's ramparts - now a park - is fun: check out the windmills and medieval city gates:
https://www.visitbruges.be/en/brugse-vesten-bruges-city-ramparts

As Renee said, it's a great town just to walk, and my favorite hours to wander the streets were the quiet ones early in the morning and later in the day. You can exhaust a camera's memory card in a big hurry!

For the Bell Tower, I would plan to be there when it opens. Otherwise, the line can be long since they only allow 25 people at time.

I think the Church of the Holy Blood is spectacular.

A boat trip along the canals is a wonderful way to see the city.

When I went, the line up for the bell tower was lengthy, so I second the recommendation to get there early..

I think the Church of the Holy Blood is spectacular.

Oh yes, that one too. I left it out as I may have already given the OP more than they can manage and didn't even get around to BEER! Very good beer in Belgium. We had many happy beer o'clocks. 🍺

We skipped the top of the Belfry: done enough Tops Of Big Tall Things here and there to be sort of allergic to the queues and crush usually involved.

i would go to the Church of our Lady and Sint Jans Hospital and the Bell Tower.
Can easily see all three and still have time to wander, around, sit in the Korenmarkt and enjoy the scenery.

Additionally, there are the windmills, toll house and Van Eyck square, St. Bonifacious bridge near Church of Our Lady, and old city gates. All can be seen just walking around. You could also take the tourist boat canal ride that provides a city view from a different perspective. You pick it up from any number of locations in the Rozenhoedkaai street area. Only after seeing everything everybody mentioned would I visit the Choco and Fries museums.

sit in the Korenmarkt and enjoy the scenery.

As far as I know there isn't anything called "Korenmarkt" in Brugge (there is in Gent). The central square is simply called the Markt. Just don't want the OP to go looking for something on a map that isn't there! :O)