Katelyn,

What you need

Jar, 1 Gallon
Cucumbers, 20-30 or enough to fill the jar
Water, 1/2 Gallon
Salt, 140 grams (see below for conversions)
Garlic, fresh, 2 medium cloves/sections (or 3 small, or 1 really big)
Dill, fresh, several whole stalks, like 5-10 (amount not critical)
Pickling Spice, dried, 2 Tablespoons (okay to eyeball, amount not critical)
Plastic bag

Ingredient Notes

I use a 1 gallon glass jar, but you could also use a ceramic crock. Just not
plastic. Exact size is not critical. Scale up or down as you like.

Cucumbers should be specifically for pickling. They would probably be labeled
"pickling cucumbers" in the store or I usually use "Persian picklers" or
Persian cucumbers which are a little straighter than the standard pickling
cucumbers. Either work fine. I get mine at a local Asian market because they do
not put wax on them there to make them look a shiny. I would avoid waxed
cucumbers if you can. Get as many as will fit in your jar.

I use plain tap water but I have heard that some tap water is too high in
chlorine and will prevent fermenting. If yours is, you could get a gallon from
a water vending machine if they have that in your area. Or a jug from the
store.

I use "canning/pickling salt" which is just plain salt but it's ground up finer
so it dissolves better in water. If you can't find it locally, it's on Amazon.
Kosher salt will work fine but give it more time to dissolve. If you can't get
these, you could use plain non-iodized table salt. It has anti-clumping stuff
in it, so it is not preferred, but I've used it in the past. Really any salt
will probably do, but don't use expensive fancy salt and definitely not pink
curing salt (used for meat curing).

No scale? 
Morton Canning and Pickling Salt   1/2 cup plus 2 Tablespoons
Morton Kosher Salt                 1/2 cup plus 1 Tablespoon
Table Salt                         1/2 cup *minus* 1 teaspoon

Pickling spice is a pre-mixed assortment in the dried spices section of your
store. I like Morton & Bassett, which is also available from Amazon, but any
brand, even store-brand will be fine.

Make Pickles

Put the cucumbers in a big bowl or your sink and fill it with cold tap water to
cover. Some time soaking is preferred, so do this first.

Wash the jar well with soap and hot water.

Make the brine in a different container (not the jar, a pitcher with a spout is
convenient) with 1/2 gallon of water mixed with 140 grams of salt. Stir or let
sit until salt is dissolved. Slightly warm water is fine, if it helps to
dissolve the salt.

Scrub/rub the cucumbers with your hands to make sure they are clean. Trim both
ends a tiny bit to remove the blossom and the stem end.

Smash the garlic with the side of a knife and add to the empty jar, with or
without the skin, along with the dill and pickling spice. Pack the whole
cucumbers in the jar vertically, as many as will fit. It's better if they are
touching and tight, but not so tight they get smushed. If there is room on top,
add more horizontally, as many as will fit.

Pour in salt water to cover all the cucumbers. Discard unused salt water. If
you can, wedge the top layer of cucumbers in so they don't float and prevent
the ones below from floating. If they don't stay submerged, put something heavy
on top like a clean glass filled with water. Use a plastic lid under the glass
if it helps. Cover the jar loosely with a plastic bag or plastic wrap. It
should not be airtight, but prevent stuff from falling in. You might want to
put a plate under the jar to catch any spillover from bubbling.

Put in a shady spot on your counter or somewhere room temerature. Uncover every
2 days and skim off any scum or bubbles (there will be both, it is expected).
After seven days you can check every 2 days for doneness. Fish out a cucumber
and cut a little bit off the end. They are done when the color inside is the
same dull green as the outside. If they are still light yellow inside, put them
back for another day or two.

When they are done, I transfer the pickles to another, or multiple, containers.
Plastic is fine. Then I strain and save all the liquid and discard the spices
and stuff. I use the strained liquid mixed 90% with 10% plain water (eyeball
it, not a critical ratio) to cover the pickles in the new containers. This
tends to keep the pickles from getting saltier. Then I put them in the
refrigerator. But it's also fine to just put a tight lid on the whole gallon
jar and move it straight from the counter to the 'fridge as-is, without
straining or anything.

Enjoy,