Is linking necessary to download files?

Okay, that did allow me to get an access token and secret. However, I still don't seem to be able to retrieve a file from my folder using this method. If I login normally to link my dropbox, it does work. (I basically pull a text file from my Dropbox and display the text.) I'm not sure what I'm doing wrong here. The one thing I did notice was that I get a new access token and secret every time I login normally. Do the tokens expire? Anyways, here is my code cutting out irrelevant portions and replacing sensitive info:

In my app delegate:

.h

#import <UIKit/UIKit.h>


@interface AppDelegate : NSObject <UIApplicationDelegate>


@property (strong, nonatomic) UIWindow *window;


@end 

.m

#import "AppDelegate.h"
#import <DropboxSDK/DropboxSDK.h>

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
 DBSession *dbSession = [[DBSession alloc]
 initWithAppKey:@"key"
 appSecret:@"secret"
 root:kDBRootAppFolder]; // either kDBRootAppFolder or kDBRootDropbox
 [DBSession setSharedSession:dbSession];
 
 //[[DBSession sharedSession] unlinkAll];
 [dbSession updateAccessToken:@"token" accessTokenSecret:@"token secret" forUserId:@"id number"];
}


@end

In my view controller:

.h file

#import <UIKit/UIKit.h>

@class DBRestClient;

@interface homeVC : UIViewController
{
 DBRestClient *restClient;
}

@end

.m file

#import "homeVC.h"
#import <DropboxSDK/DropboxSDK.h>

@interface homeVC () <UITableViewDataSource, UIAccelerometerDelegate, DBRestClientDelegate>

@property (weak, nonatomic) IBOutlet UITableView *tableView;

@property (nonatomic, strong) DBRestClient *restClient;

@end

@implementation homeVC

- (void)viewDidLoad
{
 [super viewDidLoad];
 
 NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
 NSUserDomainMask, YES);
 NSString *documentsDirectory = [paths objectAtIndex:0];
 NSString* path2 = [documentsDirectory stringByAppendingPathComponent:
 [NSString stringWithFormat:@"%@", @"Welcome.txt"]];
 
 [self.restClient loadMetadata:@"/"];
 [self.restClient loadFile:@"/Welcome.txt" intoPath:path2];
 
 NSString* content = [NSString stringWithContentsOfFile:path2
 encoding:NSUTF8StringEncoding
 error:NULL];
 NSLog(@"%@",content);
}