When shall I plant?

Hi, just broght some garlic bulbs, red onion sets and shallots. I was wondering when I should plant them, It says on the packets next month but i was thinking of starting them of in pots next month and plant them out in march. My nan said just plant them straght in the ground in march.

also I've dug a new patch in early january and it has'nt been manured
I think its a bit late for that so I thinking what else I could use.

I wouldn't start them off in pots, there'sno need.
Just put them staight into the ground like Gran says.
The spot that hasn't had any manure will be just fine for them all.
You could add a slow relaese fertilizer like fish blood and bone, or some Vitax.You could do this now, if conditions are right, or keep the bulbs dry and cool untill next month (thats when I put in my second batch)
Don't panic, theres plenty of time yet.