Hi
"...But I find that no. In effects I tried to include a file '' subtitles '' but impossible..."
VP does not have "subtitles" in the effects shown when the timeline clip FX button is clicked. Not sure about the Free version but in the normal version you can click the Effects tab on the top toolbar and you should see a new horizontal toolbar with the most common effects used such as Crop; Speed change;Rotate etc. At the right hand end should be "Subtitles" Selecting this option should bring up the Subtitle entry screen. If you type your text in the lower section of this screen and then press the Green + , your subtitle will be created at the cursor position and listed in the upper section.
If you do not see the SUB tab in the effects toolbar then click the Home tab at the top and then the chevron at the right hand end of the toolbar. "Subtitles" should be one of the options in the drop down menu.But as I said..Not sure if the version has this.
If you still can't find subtitles use Text effect instead, followed by Simple Text Overlay. This will open a text editor. Set the font;size;colour etc. and then enter text. There are also some basic positioning options. VP will generate a text image; place in the clip bin and add it automatically to the overlay track at the cursor position. You can re-edit this at any time. You can easily position the text on the timeline exactly like an image. Use the POSITION effect to position the actual text where you want against the underlying clip.
You will find hints on how to do many things if you press F1
However come back to the forum if you want more detail.
Nat