There's no rush to do it all yet. I have a big yard and a lot of arthritis so I have to get going now.
Pre-emergent prevents seeds from germinating so you don't want to put it where you'll be planting seeds or want things to reseed. Preen is a common brand. You don't have to use it. I do because I'm old and slow and tired of pulling weeds.
Last year I made a bunch of hypertufa pots and this year I'm making a bunch more once the weather is warm enough at night.
Arrrgh, I think I have to be somewhere else this weekend. Maybe I can find a way to get to the DBG sale.