How do I plant this? Open ground plant - looks like a tangle of roots?

[MrsFogi]

I've received my "Phlox Bright Eyes- Open Ground Plants" but hadn't realised they would be an envelope of dry tangled "things". Do I just stick them in in a hole, cover them and hope for the best (and that I remember where they are an don't dig them up again!) or is there something more technical I should be doing?

is there no instructions? If not, a general rule is to plant bulbs etc about 3 x their height, depth-wise.

Decide where you want them, then dig out a larger hole than you need. Cut up the bottom with a spade if it's compacted, then add some compost, mixed in with some of the soil. Place each tangly thing carefully, if possible the right way up, in the hole and cover other with soil; pressing down lightly. Mark each spot with a cane or stick (so you don't pull them up by mistake) and water.
Then wait. And wait. Hopefully, some will come up!

if it gets dry, water regularly, especially in the 1st year as they develop their roots.

Great advice from ifailed. The only thing I'd add is - do it quickly! Bare root perennials do not like to be dried out.

Did it come with instructions?

Roots down, shoots up and as deep as the instructions say.

and soak in tepid water for an hour before planting out.