you will have to buy a book
for example the schüler duden isbn 3-441-222-7< this is the old version you will have to ask for the new one.
then you will need a dictionary english german german english the english version
there are much more unregulary verbs and so on more artikels....
then you will have to learn the words. and then you will have to buy a newspaper.
a newspaper for kids just as the bravo or so.
after half a year or so you should be able to follow the grammar.
after that you can try the grammar duden,
and the duden wörterbuch des guten stils . ..... and another newspaper.
simply ask your questions here....
the schüler duden rechtschreibung und wortkunde is used in german elementary school it contains about 15000 words
there are only 10% content you will never need and only very few necessary words missing.
2 and a half years or so.
Listening to mcs for children will help you to learn the most common irregularities. For example Grimms Märchen.