Flexbox

flex-direction

some_element {
    display: flex;
    flex-direction: row;         /* right, default */
    flex-direction: row-reverse; /* left */
    flex-direction: column;      /* down */
    flex-direction: column-reverse; /* up */
}

justify-content

some_element {
    display: flex;
    justify-content: flex-start; /* default */
    justify-content: flex-end; 
}

flex-end is always the opposite side of the element's flex-direction.

some_element {
    display: flex;
    flex-direction: row;
    justify-content: flex-end; /* justify to the right */
}