Need help wit verbs ending in the "RU" sound
 

Ok, so what i want to know is how to change these words in to past tense and negative.

I am pretty sure that to change them into negative you change ru to ra and add nai, to make ranai. But how do you put it into past tense?

First, you need to know that japanese verbs can de divided into 2 main groups, "godan" and "ichidan". Every ichidan verb ends in -る. Godan verbs have many endings, including obviously -る.
So when you have a verb you want to put in the past or negative form, you have to know if it's a godan or an ichidan verb first.

Let's take a godan verb ending in 乗る (のる). "to get on" (bike, bus, car, train...)
to make the negative form, drop the る, add ら + ない
乗る -> 乗らない
to make the past for, drop the る and add った
乗る -> 乗った

Let's take an ichidan verb: 見る (みる) "to look"
to make the negative, drop る and add ない
見る -> 見ない
for the pas, drop る and add た
見る -> 見た　　

Be very carfeul when you do this process! Never confuse an ichidan verb with a godan!! For example, the verb 走る　(はしる) "to run" is a Godan verb, so it goes like
走る-> 走らない-> 走った
and NOT
走る->　走ない->　走た

Thanks heaps!!!

I completely understand!

Also, if you don't mind telling me, how do i tell the difference between a godan verb and an ichiban verb? Is there an easy way to distinguish between the two?

If i was to say 日本語をならう　（learn Japanese), how would i change it to negative and past tense.

Unfortunately, there aren't man ways to tell if a verb ending in -ru is a godan or an ichidan. You have judge by seeing the different verb forms: if a past form ends in -tta it's a godan, in -ta it's an ichidan, if the negative form is -ranai it's a godan, if it's -nai it's an ichidan, and so on.
It's like in english, when you say, for example, that the past form of the verb "to spell" is "spelt" and not "spelled". You just know it, there's no way to determine it.
negative -> 日本語を習わない
past -> 日本語を習った

Hehe... this is helping me out too. ^_^