Dirted tanks are reasonably popular option. I think a lot of people try them eventually. That said, they are not beginner friendly. If this is your first planted tank then I strongly suggest reconsidering the dirt aspect and replacing it with a professional aquasoil such as ada amazonia, fluval stratum, uns controlsoil, etc. You can still put it under sand/eco-complete but you don't have to worry about it making as much of a mess.
You need to sift the dirt and/or soak it first and remove floating bits. You also need to treat both dirt and aquasoil as active substrates when setting up the tank, meaning they will both leech a lot of nutrients into the water right away. So for the first week after flooding you do water changes every day of 50%. Second week is every other day. Third week is 3 times that week. Fourth week is twice that week. Thereafter once a week.
Even after all this is done you will still be in a situation where uprooting plants will make a mess as dirt is pulled to the surface and you will thus need to be careful about disturbing the substrate much. Rescapes will need to be kept to a minimum / not done at all.
After all this is said and done dirt does not have much or possibly any real advantage over professional aquasoil except price and even then, this is a pretty small tank so it wouldn't cost much to put down an inch of aquasoil and cap it with sand / eco complete.
Either will require a liquid fertilizer to be added. Assuming you are not planning to inject co2 I recommend ThriveC.
Oh and the sand you see in a lot of planted tanks is probably Pool Filter Sand. The HTH brand is well thought of if you can find it locally. Otherwise any pool supply store can sell you a 50lb bag for like 15 dollars or less.