The trigger page is the only page that lets you review all 4 tracks at once, so you can see when triggers happen relative to each other. So yes, in the default configuration Kria will have a sequence length of 6 for all 4 tracks. You really have up to a 16 step sequence, and the highlighted 6 steps are showing the selected 6-step “loop” that’s playing in that sequence – you can toggle keys further to the right on the top 4 rows to see them light up, but these triggers won’t be hit unless the loop selection includes them. To move the selected loop, hold the LOOP key and tap a key in the top 4 rows other than the start of the current loop selection. Note that the loop selection can also wrap around the edge - if you hold LOOP and then tap the rightmost key, your selected 6-step loop starts on the farthest-right key on the grid and wraps around the other side to include the 5 leftmost keys.
To change both ends of the loop selection rather than just moving the start point, you use a 3-key gesture: hold LOOP, hold the desired start point, then tap the desired end point.
On the trigger page (6th key from the left on the bottom row is lit) you see all tracks, and can toggle any trigger for any track from this view. All other pages should control only the selected track (the leftmost 4 keys on the bottom row are the track selects). All 4 tracks can be programmed independently of each other. The only interaction between tracks has to do with how the loop selection works - by default the “loop sync” mode is “all”, which means that all four tracks share the same loop selection for all parameters. You can decouple track and parameter loop selections from each other by changing the options on the config page (shown when key 2 on the Ansible front panel is held).
Programming parameters within a track typically does not affect other parameters on the same track either. The exception to this is the “note sync” setting (on by default) which keeps the trigger and note pages in sync with each other – they share the same loop endpoints, and toggling a note on the note page will toggle the corresponding trigger step for the selected track, and vice versa.