In order to upload from your phone, you will need to select the "Hi ...." option in the top right-hand corner of your phone. Then select "My Media" and you will see the below screen.
Once you see this image you can select the "+" symbol and it will open up the below window. Each phone is going to look a little different, but you will need to navigate to where you have your media stored on your device. In this case, you can select "Photo Library" or "Browse" if you are using a different application to store your photos.
Once you select the location where your media is stored you will be able to select the media you would like to upload.
Once you select your media that you would like to be uploaded to your account. You can select "Done" and wait for your media to finish uploading. (upload times will depend on file size of your media and your internet connection"