What is actually in the box?

Every set on the market is built the same way, whoever made it. A rim that comes apart into curved segments, one leg for every joint in that rim, and a net that hooks onto the rim all the way round. Plus a ball, usually two. That is the whole inventory. Lay it out and count it.

"So if I only got one bag of parts, is something missing, Jakub?" Probably not. Lay it out on the grass and count: segments, the same number of legs, one net. If those three match, you have a complete set. Pumps and spare balls vary by manufacturer and by price bracket, and a missing pump is an annoyance rather than a problem, since any ball pump with a needle works.

A regulation set is 91.4 cm across at the top, which is 36 inches, and 20.3 cm high. Roughly ankle height, roughly a metre wide. If yours is noticeably smaller, you have a travel or junior version, which is fine to learn on and will feel different from the sets used at tournaments.