I've found that air drying is a great way to preserve flowers at home, it's really simple and helps retain their color and shape. Just tie the stems together and hang them upside down in a warm, dry place with good airflow, like a closet or attic. You can also use a drying rack or a paper bag to speed up the process. Another method is to use desiccant like silica gel or borax, you just place the flowers in a container with the desiccant and seal it, this method helps to absorb the moisture and preserve the flowers.