At this stage of the year and with group 2 clems I don't think they need pruning back but they do need very good soil preparation and a deep hole and a support ready to cling to. Training the stems as horizontally or diagonally as possible helps with flowering vigour.
Put them in a bucket of water to make sure their compost is thoroughly wet until no more air bubbles escape. Prepare a hole at least twice as deep as their pots and then mix some well rotted manure and/or garden compost and pelleted chicken manure into the soil. Put some in the hole then plant the clematis at least 4inches/10 cmes deeper than they were in the pot. Fill up the hole with the improved soil, firm in and water well. Water regularly in their first summer. Scatter on some slow release specialist clematis food at planting time and every spring.
Deep planting helps keep the roots cool and encourages extra stems to form for a bushier, healthier, more floriferous clematis. It also helps them recover better should they get clematis wilt. A good mulch of well rotted manure or garden compost every autumn will help protect the roots and keep them healthy over winter.
Yours are both group 2 for pruning which means they just need a light pruning after the first flush of flowers in June to remove any very old or dead stems to keep them tidy and invigorated. Removing some of the spent flowers and giving them a good liquid feed at the same time will encourage them to produce a second flush of flowers in late summer.