Last year I made some sauerkraut and some kale that turned out REALLY great, especially the kraut.

The method I am going to show you is an anaerobic process. Oxygen will totally mess it up. There are many methods but I like this one.
The first thing you need to do is prepare the equipment.
What you need first is a LARGE MOUTH mason jar and seal. Any size will work but quart and half gallon seems to work best.
I first drill a 1/2 inch hole in the seal of a mason type jar. I used a spade bit as shown. I cannot remember if I drilled a pilot hole first, but that would be helpful. 1/16 to 1/8 would work fine. Put the seal on a piece of wood, like a 2x4. Drill from one side, but not all the way through. Then flop it over and finish the hole.
Next you insert the grommet into the hole. It is a 3/8 ID x 1/2 OD grommet. I got mine on Ebay. Might need a little help with a screwdriver if your fingers are not really strong.
Like I said, this is an anaerobic process so you need something to hold the stuff under the water level. Again, there are LOTS of ways to do this. With certain product you may not even need this part.
The small one in the pic is from last year. I had to add WAY too much water and as the product released its own water, well it would have made a HUGE mess if Renee had not insisted on a bowl underneath. This year I used the BOTTOM of the jar to make my pattern. You will see in a later pic how well this worked out. No water overspill either!
You will also need an airlock. This part assures an oxygen free environment. Again, I got mine on Ebay. Just let me know if you have trouble choosing and I can help you. Do not post links to Ebay on here as the links expire.
What do you need next? ORGANIC veggies: cabbage (for sauerkraut), kale, chard are easy ones to start with. I did some carrot sticks this year. You do not have to do just one veggie either but I suggest it for your first couple of times. There are lots of recipes out there to try or come up with your own creation. This year I added garlic to my kraut! It was good, but I will add less next time.
Why organic? The little critters that you need to do the preservation live on organic veggies. Store bought MIGHT have some, but it has been so washed and processed that the population is probably minimal at best. It will take WAY too long or you might have to add something to kick start the process, like liquid from a previous ferment. Some use natural whey. I used chard from our garden this time.
You can rinse off the veggies, but DO NOT SCRUB THEM! Very important. Gotta keep the critters intact. You can also tear, chop or shred the veggies if you want.
OK, how do you get the stuff into the jar. You pound the livin' snot out of it! Literally.

Once you get about a quarter of the way up the jar STOP! You will need to add some salt now. It is suggested to use 1 tablespoon of salt per quart. Divide this in fourths. Add one portion now and at each quarter completed. I put just a bit less this time since the kale I made was too salty for me. Don't skimp too much because the salt keeps the bad critters in check until the good critters can take over.
You need to stop about an inch and a half from the top, right about where the jar starts necking down. This allows plenty of room for an air gap at the top and to top off with water to COMPLETELY submerse the veggies. The air gap will be the take up for any liquid released during the ferment as well. For veggies with LOTS of moisture, like cabbage, you might want to drop to two inches. You can always put the jar into an overflow container though, so no big deal.
OK, you have your veggies all nice and crammed into the jar. Now you insert the hold down device and top off with any needed water to just cover them up. You want room for water expansion as I already described.
Install the seal and ring, insert the airlock into the grommet and find a warm place out of direct Sun to put the container. As in the picture above write a date on the jar. Maybe even write down what you put in the jar if you did a recipe.
WARM PLACE???? Yes, the critters that do the work like to have temps between 70 and 80 degrees f. Trust me, it works out just fine. It is OK if it is cooler, it just takes a bit longer. Too hot would be a bad thing to do though. It will kill your colony of critters.
After 3 to 5 days the fermentation should be done. The length of time determines how strong a flavor you wind up with. My sauerkraut I did for 5 days. I cannot remember how long I did the kale for. Once the time has passed replace the airlock seal with a regular seal and put in the fridge to stop the process. You can actually try it out before you cool it off.
Here is my finished sauerkraut from last year. Notice how it had a slight change in color? Not all produce will change like this.
WARNING! If you do not make enough you may not have any to put into the fridge.

One of the things I hope to do this year is make FERMENTED SALSA!!!!!!!!

If you do things correctly all should be fine. People have been doing this for hundreds of years. That being said, here are the
Obligatory warnings: If it does not smell right (rotten egg or sewer smell) then it probably is not right. My first attempt was some green beans (sans salt) that did not turn out. There will likely be things floating around that will make the water less than clear. That is OK. If there are noticeable signs of mold down in the water toss it. If there is just a touch on the surface, scoop out the top bit and give it a chance. That probably came from a bit of material poking it's nose up out of the water. Educate yourself, do some reading and watch some vids.