Hey
You don't use your units effectively. They're idle all the time. However this is completely normal for a beginner you just need to practice more and eventually you will get better ! It's hard to give any substantial advice before you reach a certain level because theoretical advice only makes sense if the player has basic knowledge of troop movement and positioning.
Here's a build order to practice with:
Early Game:
Volks, Volks, Volks, Medic Truck
Mid game vs USF:
Raketenwerfer, 1 Schreck on a Volks, 2 Panzerfüsiliere, Depending on what your opponents army looks like you equip G43 (vs Infantry) or more Schrecks (vs Vehicles)
Mid game vs Soviets and Brits:
Infanteriegeschütz, Panzerfüsilier, Raketenwerfer
Late Game:
Flak Truck, Panzer 4, more Füsiliere/Raketenwerfer/Volks
General Tips:
- keep your Infanteriegeschütz next to your med truck
- don't build a Kübel
- don't build additional Sturmpios unless you lose your starting unit
- focus on microing your infantry units as effective as possible
- always reinforce your units ASAP and get them back on the field quickly after retreating
- don't build panthers in 1v1