I have spend plenty an afternoon, sitting along the local shipping canal or one of the fishing ponds in the area, when I was a child.
If I was lucky there was a three part cane fishing pole and if I was unlucky I got the use of a bamboo one piece 'pole' which was a bean stick if not in use for fishing.
Tie the end of the string to the top of the pole, the purpose made one had a loop for that, the bean stick ones required a bit more tying skill.
The roll the line from the holder till you can hold the pole and holder comfortably and walk to the water, roll the rest of the line from the holder and attach bait to the hook, move the top of the stick out over the water and lower it till the float floats and wait till it dips or till you run out of patience, pull out, attach new bait and repeat. At the end of the day you would roll the line on the holder again and bring it home that way, to be used an other day.
In all the years of fishing I managed to get one carp, and that scared me out of wanting to try again.
Others in our area had a little more luck with the ready made lines but most people who were serious about angling would not use the ready made ones, those were for the kiddies and sometimes the partners (mostly wives) who did not really want to fish but wanted something to show why they were there.
This kind of line and set-up is not for serious fishing, it is really a kiddies starting set and needs a pole to use it. (Although some people did use it with just a bit of wood to hold it in hand and pretend not to be fishing when the licenses were checked.
In a comment to an other answer there is a link to an other kind of fishing starter set, which is a simple but not basic pole with a winder, string and tackle. While still mostly a play thing, it is way over the one in the question. I would not expect this one to be used in serious fishing, adviced ages are 6 to 12 years, pole lenth 1.55 meter, but they do look like the poles serious anglers use.