navigate files on sd card (arduino meg+sdcard+lcd 12C)

hi,
i have a project for my school and i'm kinda stuck. i will describe what it is suppose to do:

-on sd card i have .csv files
-i have to list them on lcd
-i have to navigate using buttons
-choose 1 file from there and open it pressing a button
-sent it via serial1

what i managed to do is to config the lcd and read the sdcard, and list the files on serial. i need some help from you guys, maybe you have some ideeas how to solve this.

here is my code so far.

#include <LiquidCrystal_I2C.h>
#include <SPI.h>
#include <SD.h>
#include <Wire.h>
//-------------------
Sd2Card card;
SdVolume volume;
SdFile root;
const int chipSelect = 53;
//-------------------
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);  // Set the LCD I2C address
//-------------------
/*
The circuit:
  * SD card attached to SPI bus as follows:
 ** 50-MOSI - pin 11 on Arduino Uno/Duemilanove/Diecimila
 ** 51-MISO - pin 12 on Arduino Uno/Duemilanove/Diecimila
 ** 52-CLK - pin 13 on Arduino Uno/Duemilanove/Diecimila
 ** 53-CS - depends on your SD card shield or module.
 	
 SPI	Uno	Mega
SS	10	53
MOSI	11	51
MISO	12	50
SCK	13	52
	Pin 4 used here for consistency with other Arduino examples
 */

void setup() {
  Serial.begin(9600);
  lcd.begin(20,4);
  lcd.setCursor(4,0);
  lcd.print("Programator D");
  delay(2000);
  lcd.setCursor(0,2);
  lcd.print("Initializing SD...");
  pinMode(53, OUTPUT);
  
  if (!card.init(SPI_HALF_SPEED, chipSelect)) {
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("init failed. Check:");
    delay(1000);
    lcd.setCursor(0,1);
    lcd.print("* card in ?");
    delay(1000);
    lcd.setCursor(0,2);
    lcd.print("* wiring ?");
    delay(1000);
    lcd.setCursor(0,3);
    lcd.print("* chipSelect pin ");
    delay(3000);
    return;
  } else {
    lcd.clear();
    lcd.setCursor(0,0);
    lcd.print("Wiring is correct");
    lcd.setCursor(0,2);
    lcd.print("a card is present.");
    delay(2000);
  }
  
   // print the type of card
   lcd.clear();
   lcd.setCursor(0,0);
  lcd.print("\nCard type: ");
  switch (card.type()) {
    case SD_CARD_TYPE_SD1:
      lcd.println("SD1");
      break;
    case SD_CARD_TYPE_SD2:
      lcd.println("SD2");
      break;
    case SD_CARD_TYPE_SDHC:
      lcd.println("SDHC");
      break;
    default:
      lcd.println("Unknown");
  }
  delay(2000);
  lcd.clear();
  lcd.setCursor(0,0);
  // Now we will try to open the 'volume'/'partition' - it should be FAT16 or FAT32
  if (!volume.init(card)) {
    lcd.print("No FAT16/32 part.");
    lcd.setCursor(0,1);
    lcd.print("format the card");
    delay(3000);
    return;
  }
  // print the type and size of the first FAT-type volume
  uint32_t volumesize;
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print(" Volume is FAT");
  lcd.print(volume.fatType(), DEC);
  delay(1000);
  //lcd.println();

  volumesize = volume.blocksPerCluster();    // clusters are collections of blocks
  volumesize *= volume.clusterCount();       // we'll have a lot of clusters
  volumesize *= 512;                            // SD card blocks are always 512 bytes
  lcd.setCursor(0,1);
  lcd.print("Volume size (Mb): ");
  lcd.setCursor(0,2);
  volumesize /= 1024;
  lcd.print(volumesize);
  delay(2000);
  lcd.setCursor(0,3);
  lcd.print(" Files found : ");
  root.openRoot(volume);
  // list all files in the card with date and size
  root.ls(LS_R | LS_DATE | LS_SIZE);
  delay(3000);
  
}

void loop() {
  //lcd.clear();
  

}

thank you