Balcony/window box advice

[Hoover.]

I've just purchased some zinc window boxes which I am going to hang off my balcony railings.....I'm intending to grow some herbs in them, as feed up with spend £s each week and throwing them away as only need a little.

I know nothing about growing stuff.

First off do I leave the drain holes bunged or remove the bung

Second bought some soil stuff, but do I need to but shingle or something in the bottom, or just fill up the soil stuff

I realise they need regular watering, so have also bought a watering can

Now I just need to by some herbs...... guess supermarket ones in pots, or is still ok to grow from seed ? or are there better pre-grown ones available and if so where ?

Any pointers really would be helpful

Cheers
Hoover

[Hoover.]

It looks like both my lines of thinking are plausible solutions for the soil....... the second sounds more me

I'm looking to start of with some of the more classical herbs like rosemary, mint (love a mojito and a pimms in the summer), oregano and basil......... and maybe a bit more adventurous and see if I can grow some coriander (this is my pet hate from supermarkets as it dies of quickly)

[Hoover.]

Order a selection of herbs, pretty similar to the post above........ going to keep the mint in a pot buried in balcony box, so hopefully this should keep it contained