This is the in case.
Simply add -ban/-ben to the end of the noun. If the noun ends in certain short vowels, lengthen the vowel.

Londonban lakom I live in London
Szeptemberben in September
iskolában in [a] school 

This is the  "static position" member of the triad.

	Tett könyvet az szekrénybe. He put a book into the cupboard.
	Aztán a könyv az szekrényben volt. Then the book was in the cupboard.
	Azután, vitt könyvet az szekrényből. After that, he took a book out of the cupboard.

Generally, flat surfaces use this triad: table, street, face, etc.

Most Hungarian cities and Hungary itself use this case:

• Budapestre megyek. I am going to Budapest.
• Budapesten vagyok. I am in Budapest.
• Budapestről jövök. I am coming from Budapest.
• Magyarországról vagyok. I am from Hungary (i.e. I am Hungarian).

Essentially any three dimensional object that has an inside, such as a box or waldrobe, uses this triad.

I cannot stress this enough. In Hungarian there is a grossly different sense of whether something is in, or on, or by/at. It's actually more sensible than in English, and then have three distrinct groups of nouns. See noun locations. However, it is incredible confusing to choose the correct equivalent of our preposition. You can really only learn this from experience, but if in doubt I think -ban/-ben is appropriate.

Essentially, any noun that goes in the into/in/out-of group uses -ban/-ben for the static position. Conversely, any noun that uses -ba/-be for the towards movement, or -hoz/-hez for the away movement, will use -ban/-ben for the static position. Note that most Hungarian cities do NOT fall into this group: one lives "on" Budapest, and travels "onto" this city.

Some unusual uses of this:

buliban in (at) [a] party
irodában in (at) [the] office

As with so many other cases, when a definite article is used, the -ban/-ben applies to the noun and the article.

See: demonstrative pronouns.