How can I add more than 1 quantity?

Yes, you can edit your cart.

1) Go to the cart.
2) You can change the quantity by manually editing the number of items you want to buy.
3) Click on update my changes button to save your cart.

1) Please go to the cart. (DESKTOP VIEW)

2) You can change the quantity by manually editing the no. of item you want to buy. 

(DESKTOP VIEW)

2) MOBILE VIEW