cold frame - need some help

We bought a property in fall and it came with 3 gardens. One of them comes with a cold frame (wood frames with heavy plastic). Judging by their garden which we saw last summer it works great. They had an head start on everything that grew there. If we can figure out how to put it up, I would love to use it! The garden is fairly large (~1200 sqft) and the cold frame covers the whole thing.
I have never had a cold frame so I am not quite sure when to do what.
We are in zone 3 and the last frost day is usually around end of May.
We plan on using this for annual vegetables (beans, zucchini, squash, carrots, cabbage, lettuce, beets, turnips, salsify etc.). I would like to direct seed as much as possible. There are some strawberries left from last year in there so I would keep these for now.

Can anybody run me through the timelines and what to do?

Of the veggies on your list, only the beans, zucchini, and other squash are going to need the cold frame; the others are frost tolerant and can be direct seeded.  That said, a cold frame will help the others to get a month's head start on being direct seeded in an open field.  Start your beans and squash 4-6 weeks before you plan on opening the cold frame for good for the season.

Salsify is not really a domesticated vegetable; direct seed it and let it do its thing according to its own time table.  Since I live in a place with mild winters, I have salsify coming up anytime from October to February.  All of it pretty much goes to seed in May, though.

Thanks John. That sounds like a good plan. Definitely want the earlier start. We have a very short season here.

I'm also in a mild climate, so I'm just brainstorming here, but can you combine starting plants indoors with using a cold frame to get from your short season? That is say, start you plants like squashes and tomatoes indoors and then plant them under the cold frame a month before the season starts?

I only have 1 years woth of experience playing with a cold frame... What I found is that you can kill the plants very quickly by letting it over heat.  I was not home during the day to open it so it got stupid hot really quick.  Instead of killing a bunch of plants I left the frame on an empty bed to help heat/thaw the ground faster.  I start a lot of stuff indoors and usually plant out a week or so ahead of the last frost date.  At that time if you know it'll be cold overnight put the frame back on, but if not don't worry about it.  This year I'm going to try using wedges to keep the frames open a little to hopefully find the "sweet spot".