Summer plants: plant out after last frost in April or May.  Okra is among the least tolerant summer crops when it comes to early spring chilly nights.  Wait until nights have mellowed and are mostly above 50 to plant out.
 
Okra plants are sold in jumbo 6-packs, ready to plant.
 
Space plants 18"-24" apart.  No support is needed.
 
Variety information:
Clemson spineless: A classic green okra variety that has been around for generations, without anything coming along to beat it.  While supposedly "spineless", I still strongly suggest gloves and long sleeves for harvesting.  Harvest when pods are up to about 4 inches long, or at your preference.
Burgundy: Deep red okra pods on plants with red stalks and reddish green leaves.  We first started growing red okra because it was pretty.  Now I consider a good companion to Clemson Spineless, as they tend to peak at different times of the season and even out the harvest.  (And it's still pretty.)