Please help! i have trouble with learning kanji ....

I'm learned how to read hiragana and katakana after a few weeks and i'm started to learn kanji , ppl adviced me if i'm learning kanji i should start with the jojo kanji first(1945 most daily used kanji of japanese language) but recently i visited some sites and they say that jojo kanji is not even common in japan .
They said that they learned jojo kanji and went to japan and couldn't even recognized some kanji written at the station also most of the kanji in jp games and songs isn't written in jojo kanji , so even if you learnd all that 1945 kanji you would still have look up the dictionary all the times . Is that true?

And i don't know where to start first (Grammar or kanji first or learn how to speak and listen japanese) some kanji even have multiple meanings and readings ( some hiragana even have meaning too like どこ and きっと ) They say that only kanji have meanings and hiragana is only used for particles and verb endings so why there are hiragana that have meanings . So where can i learn those words and what is a good way to learn kanji?

Also some kanji have multiple readings like 上 has 3 on-reading and 15 kun-reading how many reading should i remember with words like that? Is there a way to know what reading are more common?

p/s: Is learning japanese by yourself possible?

Learn Japanese. You'll learn kanji gradually as you learn the language. Nobody learns all the kanji first and then starts learning the language; that would be idiotic.

You refer to "jojo kanji", but I assume you mean "Joyo kanji", of which there are now 2,136 (previously 1,945). By and large these are the most common kanji, and most learners concentrate on them to start with. To say that they are "not common in Japan" is ludicrous. There are other kanji outside this list that you will encounter from time to time, but if you know the Joyo kanji (as well as knowing the language itself, of course!) then you will be able to read most ordinary modern Japanese texts fairly satisfactorily (I do not know specifically about games and songs). Proper names (names of people and places) are a slight exception because non-Joyo kanji are more frequent in those. In fact, there is another list, called Jinmeiyo kanji, which contains a whopping 861 more characters "officially sanctioned" for use solely in names.

Because it takes a long time to learn 2,136 kanji, it obviously makes sense to learn the most common ones first. This should happen automatically if you follow any sort of sensibly structured learning programme. As Mike says, it is daft to try to learn kanji in isolation from learning the language itself.

In my opinion it is possible learn to read Japanese by yourself, with the help of textbooks, websites etc., and maybe with some help from people at forums like this. Expect it to be hard work and to take years. However, I do not believe that it is possible to become competent in conversational Japanese without having a huge amount of practice with other speakers, preferably native speakers.

Kanji are learned from context and words. It is very hard to learn them invidually.