Pass the filenames to vy as arguments on the command line:

vy file1 file2 file3 file4 ...

It would open four tabs.

It is possible to open files from command lines in different panes/tabs.

Consider you have three files, alpha, beta, gamma.

if you type in a terminal:

vy -p alpha beta -p gamma

The vy editor will open these three files in one tab. It will look like:

|Alpha|
----------------
| alpha | beta |
----------------    
|    gamma     |
----------------

If you hve four files, alpha, beta, gamma, zeta then you type:

vy -p alpha beta -p gamma -t -p zeta

It will open alpha, beta, gamma in a tab and zeta in other tab:

|Alpha|zeta|
----------------
| alpha | beta |
----------------    
|    gamma     |
----------------

The zeta tab would look like:

|Alpha|zeta|
----------------
|              |
|     zeta     |
|              |
----------------

The parameter -t stands for 'new tab', -p stands for 'panel', in this way you control how your files get opened.