54 square feet isn't really all that big of a garden, to be honest. :) No one can really help you on what to plant or how much of something to plant as that's a very personal matter and is dependent on what each person/family likes and dislikes. It's something you'll have to find out on your own.

"I have also noticed on some seeds it states to plant outdoors before the
last frost, there is still a lot of snow here even though the weather
is warming up, do I just dig out the snow to plant or wait until it's
fully melted? Or is there something that can keep the plot snow
free-ish?"

Generally most wait until the snow is melted and the soil has dried out some and warmed up at least a bit before planting. Can you shovel the snow off to make this happen quicker? Yes, you could but you'll still have to be mindful of soil temps. I guess you could throw a tarp on the garden but it's not something I would do.

"Also how much manure would be needed for the plot and do you have any recommendations for trellises, fertilizers etc?"

Different crops can very different nutrient, trellising, and/or watering needs as well as different pests/diseases. So, it'd help if you mentioned what you're thinking about
planting. It'd also help if you gave your general location (doesn't have
to be specific).

As for the manure, putting it where you plan on growing root crops might not be wise since the nitrogen in the manure could make the plants not grow roots or make the roots hairy (as can over fertilizing). Also, you should be aware that when using raw manure, 3-4 months between the application of the raw manure and harvest is recommended.

Hope this helps some.

Rodney

54 square feet is a lot if you're using the square foot gardening method.

Every state has a Master Gardener program, so you can check out their website for information relevant to your growing conditions. Master Gardeners

I would recommend you read the Square Foot Gardening book. If you don't want to buy it, it is available in many libraries. They also have a website.

Fertilizer isn't that complicated. There are several brands of organic vegetable fertilizer that you can use.

Plant and trellis your taller crops to the north, unless you are in the southern hemisphere. That way they will not shade the shorter plants.

My Square foot garden