First off, kudos for learning a new skill, and in the most difficult possible way! Don’t give up. Might make you feel better to know that custom mills (where you pay them to turn your will into yarn) will refuse wool with too much vegetable matter. It is hard to deal with.
I learned to spin at about 7. Self taught, as my mother is a knitter but not a spinner.- neighbor cut a circle out of an old countertop, stuck a dowel through the center, sharpened one end, and put a metal hook through the other. He also was not a spinner… but I used it by resting the pointer end on the floor, which actually was easier for learning. My mother got me a nice batch of precarded wool. The yarn was terrible. So was the next batch she got me. It probably took 2-4 lbs before I got decent looking yarn. So really, don’t get discouraged.
A few possibilities to make it easier: first, look up willowing wool. I think there is a good thread and video on this site. It is a way to get rid of some of the vegetable matter and prepare the wool for carding without expensive equipment. You will still have to handpick.
Second, take advantage of the youtube videos others recommended for carding. It won’t magically make your yarn good, but a nice fluffy even roll will certainly help.
Third, for joining the next piece of wool: don’t wait until you have a little tuft. When the previous roll is maybe 3/4 gone - but with a good palmful left - lay the next one on and start feeding iff both. Much easier this way. Take it slow, and don’t give up!