Pictures shown are mature trees for sake of reference. 
This product is sold in seedling size (18-24") bundles of 25.
(Not full grown)
 
Lilacs may take a few years to bloom after planting. 
Once established, lilacs can live a long time.
Lilacs need pruning immediately after blooming to promote flowering the next year.
Lilacs usually produce new growth (suckers) from the root area.
Planting a variety of lilac species and hybrids can provide continuous fragrance and extend the bloom time into early summer.
 
Hardiness zone: 3 to 7 depending on the species.
Full sun (6+ hours); less sun reduces flowering and increases powdery mildew.
Moist, well-drained soil; avoid wet soils with poor drainage.
Soil pH 7.0 to slightly alkaline. Have your soil tested by the U of M Soil Testing Lab.
Space new plants based on mature size. 
Planted too close, lilacs will require more pruning and will reduce bloom. 
Proper spacing increases air circulation and reduces powdery mildew. 
Once the lilac is established (2 to 3 years after planting), fertilize every few years with an all-purpose shrub fertilizer. 
Avoid applying lawn fertilizers near or around lilacs as the high nitrogen content will increase leaf production and decrease flower production.
Water after planting. Make sure the soil drains easily and does not pool. 
Poor drainage can result in stunted growth, fewer flowers and root rot.
 
Excerpted from and for more information see: https://extension.umn.edu/trees-and-shrubs/lilacs