Welcome newbie to the joy and frustrations of gardening.

We call sowing seeds directly in the ground "direct sowing". Winter sowing is sowing seeds in a covered container and setting the container outside in the winter/early spring and waiting for the seeds to germinate. I haven't been reading the forum regularly so don't know if you have been posting about winter sowing as well as direct sowing. If you need more info on winter sowing there is a link at the top of the page for FAQ (frequently asked questions).

Yes, the mulch will need to be removed. That can be difficult to do without moving the seeds here and there or even scooping them up with the mulch. You may still get some germination but you may have seedlings in places you didn't expect. It would be helpful to know what seed you planted and your zone.

Different seeds have different germination requirements. Some seeds can be covered lightly with soil while others need light to germinate and should not be covered at all but just pressed lightly to make contact with the soil. Also different seeds need to be sown at different times in relationship to your last frost date. Soil temperature also will determine when different seeds will germinate. This info should be on the packet back or you can find it online.

Here in z:4 only a few cool weather/soil seeds can be direct sown at this time. But even in Z:4 most seeds can still be winter sown.

You may want to check the other forums page to see if your state/region has a special forum where you can repost your question to get an answer from someone in your zone.

Good luck.