Loop mode and Studio mode in Loop by Zaweba
Loop by Zaweba has two views of the same song: a simple Loop mode for arranging, and Studio mode with the piano roll, instruments, mixer and effects.

Two people open a music program for the first time. One wants to drag a few loops around and hear something that sounds good within minutes. The other wants to draw notes, shape a synth and balance a mix. Loop by Zaweba serves both with two modes that look at the same song in different ways, and you can move between them at any moment.
Loop mode is the simple default. Studio mode adds the tools under the grid. Press F2 for one and F3 for the other, or choose them from the View menu.
What Loop mode shows
Loop mode keeps the screen to three things: the grid of tracks and bars, the loop library and the transport bar. Tracks run down the side and bars run across the top. You browse the library, click a loop to hear it in time with the song, and drag it onto the grid, where it snaps to the bars. The transport bar plays, pauses, records and sets the tempo you chose for the song.
That is enough to build a whole track. Starting a song with File > New song asks only for a genre and a tempo and gives you an eight-bar starter of drums, bass, chords and a lead, so you can begin by changing something that already plays rather than facing an empty page.
What Studio mode adds
Studio mode keeps the grid and library, and adds a row of tabs underneath: the piano roll, the instruments, the chord helper, recording, the mixer, effects and automation. These are where you edit individual notes, choose and shape sounds, record a microphone or a MIDI keyboard, balance the tracks and add reverb or delay.
Nothing about the song changes when you switch. A clip you dropped in Loop mode is the same clip you open in the piano roll in Studio mode. Effects you set in Studio mode keep playing when you go back to Loop mode. The modes are two views, not two projects.
A sensible way to work
Many people find it natural to arrange in Loop mode and refine in Studio mode. Build the shape of the song first: an intro with just drums, the bass coming in, chords in the middle, a lead at the high point. It's quick to try ideas when the screen is uncluttered.
Once the shape feels right, press F3. Open a clip in the piano roll to change a few notes of the melody, try the chord helper if the harmony feels flat, then go to the mixer to bring the drums down a touch and send the lead to the reverb bus. Press F2 again whenever you want the bigger picture back.
Who each mode suits
Loop mode suits beginners, young people making beats for their videos and anyone who wants a track without learning music theory first. Loops follow the song's key and tempo by themselves, so things fit together.
Studio mode suits the moment you want more control: your own melodies, recorded parts, a better balance, sound design on the synth. It is the same app, so you grow into it rather than moving to something new.
Common slips
The commonest is thinking Studio mode is a separate, harder program and never opening it. It isn't; it is the same song with more tabs. The other is staying in Studio mode all the time and losing sight of the arrangement under all the panels. If the song has stopped moving forward, go back to Loop mode for a while and think in sections rather than notes.
Both modes are part of Loop by Zaweba, free and offline, so there are no locked features and nothing to sign in to. Press F3 when you are curious and F2 when you have seen enough.