I need some gardening tips, please! I am a first time gardener.  

If you live in a moderate climate, you can put the melon and pumpkin seeds directly in the ground. Follow the directions on the package. Pumpkins take a LOT of room, so plan accordingly. Both pumpkins and melons like sun.

Lilacs like sun. Dig a hole about twice as big as the root ball and twice as deep, put some compost and/or peat moss with the dirt and mix it up really good, then plant the lilac at the point where the trunk becomes root, spread the roots gently and cover with the soil, pack down lightly, and water.

You can also talk to it and gently touch it. Really.

Lilac trees does very well in full sun,mine keeps expending every year slowly but sure. Pumpkins seed you put 5 seeds per hill. Watermelon like warm weather if you have a cool summer they won't like it. when you plant tomatoes start them indoor at least a good 2 months 1/2 before transplanting them. You can do the same with the cucumbers but they grow a lot faster. All kind of squash grow fast indoor if you are not ready to plant them outside yet start them later like only 3 weeks to a month before transplanting it.Most veggies like to be in full sun. Good luck.