Hello,
Perhaps your friend could give you a cutting a bit later in the season. Cuttings in June or July have a better rate of success.  To do this, follow these instructions from Iowa State University:

Using a sharp knife, cut off 4 to 6-inch long shoots. Pinch off the leaves on the lower half of the cutting. Dip the base (cut end) of the cuttings in a root-promoting compound. Root the cuttings in a large pot or flat containing coarse sand or perlite. Insert the bottom two inches of the cuttings into the rooting medium and firm the material around the base of each cutting. After all the cuttings are inserted, water the medium and let it drain. Cover the container and cuttings with a clear plastic bag or dome to reduce water loss. Then place the cuttings in bright light, but not direct sunlight.

Forsythia cuttings should root in six to eight weeks. When the cuttings have well-developed root systems, remove them from the rooting medium and transplant them into individual pots using a well-drained potting mix.

Read more about propagation from cuttings:
https://yardandgarden.extension.iastate.edu/how-to/propagation-deciduous-trees-and-shrubs-softwood-cuttings