The Everlasting Pea will flower best grown in full sun, although it is tolerant of some shade. It growth is similar to the annual sweet pea clinging on with tendrils and it will climb or scramble over an obelisk, trellis or adjacent shrubs. It is very hardy, H7 which means it will survive the most severe of winters. It is not particular about the soil type, acidic or alkaline, clay, etc, although it will grow best in fertile soil with plenty of moisture. Ensuring it has plenty of moisture will help to fend off powdery mildew.
Except for cutting back the Pea in the autumn, the growing conditions for the annual and Everlasting Pea are really the same. The tendrils can be a problem as it will grab adjacent plants, so it's best to check it is constraining those plants growing nearby.
I do not find it necessary to feed it or grow in particularly rich soil. The everlasting pea is vigorous and grows easily. It will flower all summer long, but to get it to do this dead heading is essential. Remove all spent flowers and seed head so that the shrub keeps producing more flowers.
It is deciduous and should be cut back to ground level in the autumn.
There is also a variety called Lathyrus grandiflorus, which you may want to give a miss as it is very vigorous, bordering on invasive, whereas L. latifolius is better behaved but in common with many climbing plants it is vigorous and will grow from 0-1.5/2m in the growing season. It can be a bit thuggish scrambling over neighbouring plants, but because it is so vigorous, if you chop it about a bit, it keeps on growing .