Quick explanation:
The numeral adjectives express a specific number or place in order. They will be explained in detail in the Long Explanation below:

Hay sólo tres carros. - There are only three cars.
Traiga usted el primer plato. - You bring the first dish.
Sólo me voy a llevar medio kilo de limones. - I will only take half kilo of limes.
Hemos alquilado una habitación doble. - We have rented a double room.

The indefinite adjectives accompany the noun adding an idea of vagueness.

¿Había algunos testigos? - Were there some witnesses?
Este hotel tiene varios botones. - This hotel has several bellboys.
todo terreno. - all land.
No tengo ninguna pregunta. - I have no questions.

Long Explanation:
NUMERAL adjectives can be divided in: cardinal, ordinal, partitive, and multiple.

Cardinals accompany the noun indicating the exact quantity or number, for example: uno (one), dos (two), tres (three), cinco (five), etc.

cuatro bicicletas. - four bycicles

treinta y un estudiantes. - thirty-one students.

doce jugadores de fútbol - twelve soccer players.

Ordinals indicate the number in order. For example: primer (first), segundo (second), tercero (third), quinto (fifth), etc.

el primer inventor - the first inventor

la tercera novia - the third bride

el décimo mandamiento - the tenth commandment

Partitives indicate a fraction of a number. For example: medio (half), tercio (third), quinto (fifth), etc.

media naranja - half an orange

la tercera parte - the third part

Multiples indicate a number several times. For example: doble (double), triple (triple), quíntuple (quintuple), etc.

doble peso - double weight
triple ración - triple serving

INDEFINITE adjectives give a vague idea. They are somewhat similar to the indefinite article un. Let's see different indefinite adjectives:

algún, alguna, algunos - some	ningún, ninguno, niguna - none
cada - each	varios - some, various
todo, todos - all	mucho, muchos, mucha - much
tanto - so much	tantos, bastantes - several
cualquier - any	demasiado, demasiadas - too much, too many
cierta, cierto - certain, some	poco, pocos, pocas - a few

They have a special form used when the adjective precedes a masculine singular noun:

alguno:    algún  alguna   algunas    (some, any) 
ninguno:   ningún ninguna (ningunos ningunas)  (no, none)