I am new to this community and i do like to know some basic queries I have about IOI as this is the first time i'am going to participate in it so my queries are like

1)is it a totally computer based exam (zio and inoi)

2)i've read the previous year questions of inoi and unable to figure out how the participants have to present the answer (in code format ex java or c++)or in algorithmic form or just we have to state the logic and approach to it

because in the website i have not got any kind of info about this

3)how do i get to participate it , as it is my first time i would like to get answers form the people who have experienced the olympiad (the requirements and fee)

4)I also would like to know how you all have prepared for it (books,Study material,coaching,online resources ,etc.)