So you can play and hear the sample with mouse controlling at least?
I don’t think you can play samples by default with spacebar. Your keyboard letters are assigned as keys and they can be used to playback the selected sample. Make sure the loaded sample is active and selected from the instrument list and try to toggle record mode off in case you still don’t hear anything by pressing the letter keys.
Take note what’s the difference between an instrument and a sample. An instrument can bundle many playable samples inside and apply different effects to them. Your instruments should be listed in the main view on the right side. Click on the instruments with MB2 and see what options are available in the drop menu. There should be a visible keyboard hotkey next to the action, and if not, you might be able to set one from the global preferences.
Take also note that in Renoise you need sometimes need make different parts its GUI active by clicking different sections of it with Alt+MB1. The active area gets highlighed with yellow borders by default. This means that now the active section responds to your keyboard hotkeys. So let’s say you want to copy and paste your instruments in the instrument window / list. Well, then you must make the window active first so your hotkeys get applied there.
Loading a sample to instrument slot using the file browser should assign the sample to be playable with all keyboard letters, but this information can be further modified in the instrument’s properties through key and velocity mappings. You should be good if you just use the default file browser from the main GUI. Another thing you might want to test is switch Renoise to fullscreen mode with Alt+Enter and see if that affects the way your keyboard inputs gets recognized.
I am using Linux as well and the keyboard playback is a bit weird sometimes with VSTi plugins, it does not work the same way in Windows.
