Welcome to the community. A 37G is a great sized tank for some groups of fish.
I would spend some time at locally owned well rated fish stores, looking at which fish really catch your attention, and after visiting several stores, also adding in some other fish stores for variety, review which fish really hit the top of the list.
The create the tank for the fish you really want most. Some might have special needs, like higher or lower tank temp, lower or higher PH, living in groups, brackish water, or with plants, or maybe alone (not playing well with friends). So then you can really have the best environment, and add to that to complete the tank.
Also if you go to the article section here, you will find many articles from members and topics which might help you.
2 very easy plant types are Java Fern and Anubias. A good variety of leaf shapes and sizes for both. These plants are not truly planted in the substrate, but are added/ attached to stones, and driftwood. Wedged in the corners or attached with a coordinating toned cotton thread. They have rhizome which will rot under substrate. They grow very well with lower light and not in need of any special fertilizing or CO2
Bronze or Green Cryptocoryne are also easy low maintenance plants.
A Morimo moss ball is an easy starter too.