Unwrapping UVs is tough – no matter in which application (apart from ZBrush perhaps, where everything else is really difficult). Here’s how to get started with UV Unwrapping in Blender.
Load an object and make sure you’re in Edit Mode. This is only allowed with a single object selected. Disable any subsurface or smoothing that’s applied on the object so that we have less vertices to work with.
Next switch to the UV Editing workspace (UV View on the left, 3D view on the right). It looks something like this:
On the right hand side, make sure the Shading/UV tab is showing – it contains some vital tools for this endeavour. Choose edge selection and start marking seams for your unwrap. It’s easy to ALT-RIGHT-CLICK to select edge loops, or use the Select Menu for more funky options.