Firstly I would advise you to get a textbook to follow, like Genki or Japanese for Busy People that will introduce grammar in a logical and measured fashion.
You could also get a grammar book.
The ones from the Japan Times are probably the definitive ones but are quite expensive.
http://www.amazon.com/Dictionary-Basic- ... 00107DAD6/
The Oxford pocket grammar is a cheap alternative to begin with.
http://www.amazon.com/Oxford-Japanese-G ... 198603827/
Online have a look at Tae Kim's grammar (
http://www.guidetojapanese.org/learn/grammar ) and there is an online grammar dictionary in the paid area of this site too.
I would also encourage you to use kana and think of verb ending changes in terms of kana not romaji, it makes things easier in the long run.
You can't really use English concepts of grammar and impose them on Japanese as the language works differently and has it's own rules and constructions.
Word order isn't as fixed as English. Subject, Object etc is given by particles ( wa, ga, ni, etc etc) rather than word order.
In general it goes Subject Object Verb, but it doesn't have to.
The non-past plain form is the dictionary form of the verb in this case kiku (to listen, hear, ask)
聞く I listen. or, I will listen. (although the speaker isn't specified it could also be you/he/she/we/they depending on context)
the plain past is 聞いた。kiita. I listened.
The construction for a continuous action ("-ing") is ~te iru
The te form of the verb and the verb iru in the form you need it to be (masu, plain etc etc)
and yes the rules for the te form depend on whether a verb is ichidan v1 (so called group 2) or godan v5 (so called group 1)
聞いています。kiite imasu. I am listening (polite)
聞いている。kiite iru. I am listening (plain)
聞いていました。kiite imashita. I was listening (polite)
聞いていた。kiite ita. I was listening (plain)
I like to listen (to music) maybe isn't a good example but it'd be
音楽を聞くのが好きです。ongaku o kiku no ga suki desu. (polite)
音楽を聞くのが好きだ。ongaku o kiku no ga suki da. (plain)
no is used to nominalise the phase ongaku o kiku to listen to music.
like (suki) is used as a "na" adjective or noun (adjectival noun I think it's classified as) in Japanese not a verb. more along the lines of X is likeable.
(You can also only make direct statements about what is liked by yourself not other people...)
(oh and nihongo is used far more often than nippongo as the reading of 日本語)