Haha yea ive been doing landscaping for a long time since I can remember, always liked gardening and stuff. Mulch like you bought, decomposes really fast, so weeds will grow really quick (cedar chips last a long time). If you put landscaping fabric underneath, which lets water through, it doesnt decompose as fast and blocks 90% of weeds. You also wont have to replace the mulch as often. But thats just how ive been doing it.
Otherwise you can always go around every month or 2 and spray for weeds too.