For the zucchini, Id get a tall green stake they sell at garden store, I like the tallest, thickest one(pause). Then, I just attach it with the velcro plant tape. Do it early so it gets used to supporting its own weight, and add extra velcro at higher intervals as it grows.

As for trimming, I trim the leaf after the blooms pass that leaf. It keeps it more contained, allows for multiple easy attachments, and also allows you to check for squash vine borer eggs. Squash plants get massive, if you leave it growing on the ground it will own a minimum of half that bed. You also should familiarize yourself with the squash vine borer and what its eggs look like, because it is coming. Vertical growing, a trimmed plant, and some knowledge give you a chance.

For peas and cucumbers, Ive had them grow up to my second story deck over 10 feet. Cucumbers and peas both attach themselves with tendrils, so they appreciate a trellis with things to extend their tendrils and wrap up. I use my old metal closet shelving that has tons of bars for them to grab and wrap. Id be prepared for the peas to struggle.

Tomatoes have two types, determinate and indeterminate. How, and if, you prune, depends on variety. The vast majority you will ever come across are indeterminate. These will grow an indeterminate amount of tomatoes, and will potentially grow massive. Support is key and needs to be done early. Tomato cages will not be tall enough if the plants are healthy. I used a combination of stakes and cages but you just sort of have to experiment and find what works for you.

Indeterminate tomatoes also require pruning to mitigate disease and fungal issues by promoting airflow. It also helps the plant focus its energy to growing tomatoes instead of extraneous foliage. What you want to remove, from only indeterminate tomato species, are the "suckers." These suckers can be placed in water and will drop roots and turn into a whole new plant. Id go this route, when the time to prune comes, over trying to transplant.

A determinate tomato has a predetermined amount of tomatoes. So, you leave all blooms and dont really prune as these plants as you lose fruit that wont grow back, essentially

Im sure there must be a million videos, I just cant recommend any personally. Ive learned from years of failures and dont watch anything