MacBook Air and use of SD card?

Hello santacull.

Welcome to Apple Support Communities.

If I'm understanding correctly, you need some help transferring data from an SD card to your MacBook Air. I will be glad to assist.

Please see the following resource:

Import photos from storage devices and DVDs using Photos on Mac

"Import from a card reader or SD card

Some Mac computers have built-in SD card slots. If yours doesn’t, you can connect a device called a card reader that is compatible with your Mac and use it to import photos from a memory card, such as an SD or Compact Flash card.

1 Insert the card into your computer’s SD card slot, or connect a card reader to your computer and insert the card into the card reader.

2 In Photos, choose File > Import, then select the photos or videos you want and click Review for Import.

3 If you selected multiple photos or videos, do one of the following:

• Import all new photos: Click Import All New Photos.
• Import a selection of photos: Click the photos you want to import, then click Import Selected.

If a message asks whether you want to delete or keep the photos on your card after importing them, click Delete Items or Keep Items.

Photos then imports your photos and videos. To cancel importing, click Stop Import.

4 When all photos have been imported, eject the card from your computer or card reader.

Imported photos appear in the Imports and Photos albums in the sidebar.

Some card readers may not be compatible with Photos. For more information, check with the device’s manufacturer."

Cheers.