Welcome to the community.
You can go pretty involved in doing a planted tank with lots of additives like an Takashi Amano - ADA style tank or use root tabs like the majority do. As you learn you can decide how to set up your tanks, but most people use sand after awhile as it looks great and has some advantages.
If you want to do some reading there are plenty of articles, in that section of the forum.
You took out your gravel so you could experience a mini cycle if your tank was already cycled. I would recommend to feed the fish lightly for a week or so and do plenty of pwc
and use a liquid test kit to verify you have good water parameters.
I love discus too but am looking for a bigger tank for that project.
Just let us know how we can help and read, read, read!!!