Can someone explain this nested condition step by step?

i'm learning steganography and stumbled upon this code, the program is work, but i would need an advance explanation since i need to present this next week. Can someone please explain this nested condition? thank you in advance

if(n < msg.length() && n < maxCh){
    if(check && pix%2 == 0 && count != 8){
        pix-=1; //what happen when count = 8?
    }
    if(!check){
        for(int spot = 0; spot < NUM_BINARY; spot++){
            if(binary[spot][0].charAt(0) == str[n]){
                if(binary[spot][1].charAt(count-1) == '1'){
                    pix-=1;
                    //what's really going on here?
                }
            }
        }
    }
    img.setRGB(i,j, pix);

    if(count%8 == 0){
        count = 0;
        if(!check)
            n++; //how can check is false when declaring check = false is not happening until the next line?
        check = false;
    }
    count++;

}