What do I do with fall bulbs that I didn't have time to plant?

You can store your extra bulbs in a container which has either vermiculite or perlite in it. (purchase at your local hardware or gardening store) Plant as many as you can first.

Place them, wrapped in paper towels, in a open cardboard box or lid. Slide the box under a bed—way under, but don’t forget them in the early spring. If any rot, the paper towels will prevent a mess. When the coldest weather is over, start planting. Share a bunch of flowers if you have too many, and just out of kindness, too. Best wishes! ☺️

If they are going to be planted in rows or groups, don't do separate holes for them, dig a trough the depth you need and place the bulbs down and fill in with the soil, that will save time and may allow you to plant more of your bulbs. If you have a garage or shed, garage is the best, you could try storing them in there. I have had bulbs survive in pots in the garage where it doesn't necessarily get as cold as it is outside. The soil seemed to give it enough protection to not freeze them too much, even in the Minnesota winters.

I’d plant them as soon as you can. I’ve planted some bulbs late and they have come up in the spring.